Black diamond brite pool with white on finish

[Aquatica]

Hi,

Hope you guys can help me out. it would very much appreciated.

I have a black diamond brite pool and it has 2 problems with it. I can solve the first but seems it might take more shocking but the other I have no clue about the white on the black diamond brite finish.

First I have a 22,000 gal black diamond brite pool which had a lot of algae.

I shocked it with 12 gallons of 10% liquid chlorine.

This morning the FC was 24 and CC was 0

I just tested again this evening and FC was 21 and CC was 1. I notice a slight smell of chlorine. not sure if it is the 1ppm of CC or the fact the chlorine level is 21ppm.

I'm guessing eventually the CC will all be oxidized as the FC is more than 10x the CC level. So maybe I wait a few day and CC will be 0.

Does this make sense? or do I have to shock again?

also if anyone knows about the white on the black finish and where it comes from I'd love to know.

Many thanks!

 

[Guest]

Can you post a pic? How 'bout full water specs?

 

[Aquatica]

Can you post a pic? How 'bout full water specs?

Its dark now but will take some photos in daytime.

Current levels:

FC: 21
CC: 1
pH: 7.6
TA: 100
CYA: 210
CH: 370

Thanks.

 

[JasonLion]

CYA at 210 is a huge problem. First off, none of the CYA tests are at all precise when measuring CYA levels that high. So your CYA level might really be almost anywhere from 150 to well over 300. Second, your chlorine is going to be far less effective at high CYA levels than it would be at more reasonable CYA levels. If CYA is really 210 you barely have enough chlorine in the pool for routine day to day use, and aren't anywhere near the FC level you would need to be at to kill the algae.

By far the best thing you can do is to replace water to get the CYA level down to something more reasonable, hopefully around 50, but definitely below 100 for sure. Until you do that, you aren't going to make much progress against the algae.

The white coating on top of the black DiamondBrite is most likely calcium. Calcium deposits on the pool surface when your PH TA and CH levels are collectively too high. You can get it off, but that is going to be a big project that best left for after the algae is gotten rid of.

I'm also concerned about your PH reading. High FC levels interfere with the PH test, causing it to read higher than it actually is. Your actual PH might be much lower. Unfortunately, there isn't any reliable way to measure the actual PH when FC is that high, so you are going to need to wait till FC comes down before dealing with that.

 

[Aquatica]

CYA at 210 is a huge problem. First off, none of the CYA tests are at all precise when measuring CYA levels that high. So your CYA level might really be almost anywhere from 150 to well over 300. Second, your chlorine is going to be far less effective at high CYA levels than it would be at more reasonable CYA levels. If CYA is really 210 you barely have enough chlorine in the pool for routine day to day use, and aren't anywhere near the FC level you would need to be at to kill the algae.

By far the best thing you can do is to replace water to get the CYA level down to something more reasonable, hopefully around 50, but definitely below 100 for sure. Until you do that, you aren't going to make much progress against the algae.

The white coating on top of the black DiamondBrite is most likely calcium. Calcium deposits on the pool surface when your PH TA and CH levels are collectively too high. You can get it off, but that is going to be a big project that best left for after the algae is gotten rid of.

I'm also concerned about your PH reading. High FC levels interfere with the PH test, causing it to read higher than it actually is. Your actual PH might be much lower. Unfortunately, there isn't any reliable way to measure the actual PH when FC is that high, so you are going to need to wait till FC comes down before dealing with that.

Thanks for the reply.

I am running a SWG so figured if I keep the FC around 15ppm that could work until the CYA came down. Yes it would be better to lower the CYA at least down to 100. I might do that. I tested the CYA by diluting the pool water 1:3 with fill water and calculated that way so a little more accurate.

I don't mind the white but like you say best to get the levels sorted out. I could always later have the pool acid washed.

 

[PoolGuyNJ]

Aim for 70 on the CYA. The only way an running pool can lower the CYA level is via dilution.

Scott

 

[Guest]

Try to avoid an acid wash. It will remove the softest part of the plaster, and with your product (DiamondBrite) it will leave it feeling like sandpaper.

I'd get your water back in line first, and then try and hold a little lower pH. The calcium will slowly come back into solution.

 

[JasonLion]

I tested the CYA by diluting the pool water 1:3 with fill water and calculated that way so a little more accurate.

Doing the CYA test with a 1 to 3 dilution give a result that is +-60 at best, and could be noticeably worse than that depending on how carefully you measured the dillution.

 

[Aquatica]

I tested the CYA by diluting the pool water 1:3 with fill water and calculated that way so a little more accurate.

Doing the CYA test with a 1 to 3 dilution give a result that is +-60 at best, and could be noticeably worse than that depending on how carefully you measured the dillution.

Thanks for the reply. I see ok. how about test strip? I also tested with a test strip and the strip said the CYA was under 300 but at least 150. then the dilution test with taylor kit tested 210. so I'm thinking CYA has to be somewhere between 150 and 300.

I have another SWG pool that has 290 CYA (tested with taylor and dilution and again test strip said under 300) and keeping FC at 15 is working well. No problems. Of course it is not summer yet so trying to get CYA down before then.

 

[Aquatica]

Try to avoid an acid wash. It will remove the softest part of the plaster, and with your product (DiamondBrite) it will leave it feeling like sandpaper.

I'd get your water back in line first, and then try and hold a little lower pH. The calcium will slowly come back into solution.

Thanks. Good advice. I was thinking the same thing. The pool has been so out of balance for ages and will take time to get sorted out. being very careful with this black diamond brite. acid washed other diamond brite pools but they really needed an acid wash due to staining.

 

[Aquatica]

Aim for 70 on the CYA. The only way an running pool can lower the CYA level is via dilution.

Scott

Thanks Scott. I've actually found 80-100 to be better for runnnig SWG's. with a level of 80-100 I'm able to keep SWG output % much lower and this extends the life of the cell if it doesn't have to work as hard.

 

[JasonLion]

Test strips are even worse than the usual black dot test with dilution. At the high end of their range test strips are +-100 when they are working, and then sometimes they are just completely wrong.

I agree that your CYA level is very very likely to be between 150 and 300. Still, that is a fairly large range.

With a SWG and CYA in that range, you can kind of get by with FC around 15 as long as nothing goes wrong. However, you mentioned that you have algae, so something has already gone wrong. Solving the algae problem is going to be a huge project with high CYA levels, to the point where it is simpler to lower the CYA level first, and then fight the algae.

If you were to try to fight the algae, with CYA as high as it is, you would need to raise the FC level up into the 50 to 80 range and hold it there for a while. Doing so would raise the PH dramatically, which would have to be compensated for least the scaling get far worse, but doing that compensation is problematic when you can't reliably measure the PH. In the meantime the presence of algae is causing the FC consumption to be far higher than it would be at lower CYA levels without algae, more than canceling out any advantage you might have had in cell life had you never gotten algae. Plus the CC levels, which you will never get rid of as long as you have algae, are likely to cause their own problems.

Higher CYA levels are indeed better for the SWG. But high CYA levels cause other issues that start to be mildly annoying around a CYA of 100 and get to be major problems when CYA is over 150. For example, it is very difficult to determine your PH with FC at 15+. The standard PH test is already off a little when FC is between 10 and 15, and gets to be completely useless somewhere around an FC level of 15 to 20. You can work around this using a mid-rnage or high end electronic PH meter, which isn't bothered by the FC level, but without that you have no idea what your PH really is. PH fluctuations are by far the most likely cause of your calcium scaling.

Both the algae and the calcium scaling are at their root caused by the high CYA levels, and both of those problems, and several others you haven't had yet, are far less likely to occur when your CYA level is more reasonable.

 

[Aquatica]

Test strips are even worse than the usual black dot test with dilution. At the high end of their range test strips are +-100 when they are working, and then sometimes they are just completely wrong.

I agree that your CYA level is very very likely to be between 150 and 300. Still, that is a fairly large range.

With a SWG and CYA in that range, you can kind of get by with FC around 15 as long as nothing goes wrong. However, you mentioned that you have algae, so something has already gone wrong. Solving the algae problem is going to be a huge project with high CYA levels, to the point where it is simpler to lower the CYA level first, and then fight the algae.

If you were to try to fight the algae, with CYA as high as it is, you would need to raise the FC level up into the 50 to 80 range and hold it there for a while. Doing so would raise the PH dramatically, which would have to be compensated for least the scaling get far worse, but doing that compensation is problematic when you can't reliably measure the PH. In the meantime the presence of algae is causing the FC consumption to be far higher than it would be at lower CYA levels without algae, more than canceling out any advantage you might have had in cell life had you never gotten algae. Plus the CC levels, which you will never get rid of as long as you have algae, are likely to cause their own problems.

Higher CYA levels are indeed better for the SWG. But high CYA levels cause other issues that start to be mildly annoying around a CYA of 100 and get to be major problems when CYA is over 150. For example, it is very difficult to determine your PH with FC at 15+. The standard PH test is already off a little when FC is between 10 and 15, and gets to be completely useless somewhere around an FC level of 15 to 20. You can work around this using a mid-rnage or high end electronic PH meter, which isn't bothered by the FC level, but without that you have no idea what your PH really is. PH fluctuations are by far the most likely cause of your calcium scaling.

Both the algae and the calcium scaling are at their root caused by the high CYA levels, and both of those problems, and several others you haven't had yet, are far less likely to occur when your CYA level is more reasonable.

Thanks Jason. Lots of good info.

There are two pools with high CYA.

One is a new client who is a princess so really hard to deal with her. This is the black diamond brite pool. When I met her pool it had signs of green algae however I did not notice all of the algae as the finish is black and this is my first black finish pool.

We installed a SWG for her and I added 2 gallons of liquid chlorine to remove the algae. However there was more algae than I noticed and 2 gallons did not do the job. This is a free form pool as well and is around 20-22K gallons. The 2 gallons just partially oxidized the matter and caused chlorimes and smell of chlorine which did not go down well with the princess at all.

When I backwashed the filter prior to shocking with 10 more gallons I noticed the DE powder I recharged with coming back out the return jets. I then realized the filter had a leak. The filter is one of those Pentair with filter grids. I finally convinced her to replace it with an EC65. After we did the water cleared up nicely. I opend the old filter and it was full of holes and slits. They had been running the pool basically with no filter. Their pool guy said they never put DE powder in cause it come out the jets. Now he tells me! lol

Anyway shocked the pool, ran pump 24/7, backwashed, recharged and now clients is very pleased with how clear the pool is. However there is a slight smell of chlorine. CC is 1ppm and FC is 21pp so it could maybe either be chlorine smelling as it is above 20ppm or maybe the CC.

Now the problem. I can shock again with 12 gallons of liquid chlorine and remove all of the CC but she is always having guests and want them to use the pool so I can not shock. So it is a catch 22..they want to swim but don't like the chlorine smell and if I shock the pool they waont be able to swim for several days until FC comes down below 20ppm.

On top of that these people do not like wasting water and most do not understand why water needs to be replaced. So yes I got my work cut out for me.

Hopefully the guest will be gone in a few days time and I can shock. They want to swim today and I've basically told my client she should smell the water first and swim at their own risk.

I will be back to the pool monday to retest.

 

[chem geek]

Anyway shocked the pool, ran pump 24/7, backwashed, recharged and now clients is very pleased with how clear the pool is. However there is a slight smell of chlorine. CC is 1ppm and FC is 21pp so it could maybe either be chlorine smelling as it is above 20ppm or maybe the CC.

Now the problem. I can shock again with 12 gallons of liquid chlorine and remove all of the CC but she is always having guests and want them to use the pool so I can not shock. So it is a catch 22..they want to swim but don't like the chlorine smell and if I shock the pool they waont be able to swim for several days until FC comes down below 20ppm.

Since the CYA is high in this pool, it will take longer for the higher FC level to get rid of the CC. Exposure to sunlight and some degree of aeration of the pool could help somewhat, especially with the smell even if the CC doesn't drop all the way. Try pointing returns up to aerate, BUT realize this will tend to raise the pH so you may need to add acid which will lower the TA level (which might be a good thing if the TA is already high -- the problem is that the higher FC prevents you from getting a decent pH reading). At a minimum, make sure the pool is uncovered. Also remember that the TA reading includes some portion of the CYA so if the CYA is high the TA will be somewhat higher as well -- 150 ppm CYA at a pH of 7.5 adds about 50 ppm to TA compared to an 80 ppm CYA pool that adds around 27 ppm to TA so a reasonable TA target for a 150 ppm CYA SWG pool would be around 90-95 ppm.

If you aren't able to do some water replacement to lower the CYA, then there are other methods of controlling the algae but they can be expensive and some have side effects. Since this is an SWG pool, the use of 50 ppm Borates can not only help control pH, but can somewhat control algae. However, adding that now and then later diluting the water to lower the CYA will require adding more Borates again later. Also, it's a challenge to add Borates to the pool when the pH isn't already where you want it. Another approach that can somewhat inhibit the algae growth (though will not clear the pool of algae) is to use a phosphate remover, but that will get very expensive if the phosphate levels are high and it will temporarily cause severe cloudiness of the pool (some phosphate remover products have a clarifier built-in for that reason). Obviously this is a stop-gap measure and is not the recommended solution because it does not address the fundamental high-CYA problem. There are other algae-killing choices, but have other side effects, such as copper that can lead to staining so I'd stay away from that (though with a black finish pool I wonder what such staining would look like).

 

[Aquatica]

Anyway shocked the pool, ran pump 24/7, backwashed, recharged and now clients is very pleased with how clear the pool is. However there is a slight smell of chlorine. CC is 1ppm and FC is 21pp so it could maybe either be chlorine smelling as it is above 20ppm or maybe the CC.

Now the problem. I can shock again with 12 gallons of liquid chlorine and remove all of the CC but she is always having guests and want them to use the pool so I can not shock. So it is a catch 22..they want to swim but don't like the chlorine smell and if I shock the pool they waont be able to swim for several days until FC comes down below 20ppm.

Since the CYA is high in this pool, it will take longer for the higher FC level to get rid of the CC. Exposure to sunlight and some degree of aeration of the pool could help somewhat, especially with the smell even if the CC doesn't drop all the way. Try pointing returns up to aerate, BUT realize this will tend to raise the pH so you may need to add acid which will lower the TA level (which might be a good thing if the TA is already high -- the problem is that the higher FC prevents you from getting a decent pH reading). At a minimum, make sure the pool is uncovered. Also remember that the TA reading includes some portion of the CYA so if the CYA is high the TA will be somewhat higher as well -- 150 ppm CYA at a pH of 7.5 adds about 50 ppm to TA compared to an 80 ppm CYA pool that adds around 27 ppm to TA so a reasonable TA target for a 150 ppm CYA SWG pool would be around 90-95 ppm.

If you aren't able to do some water replacement to lower the CYA, then there are other methods of controlling the algae but they can be expensive and some have side effects. Since this is an SWG pool, the use of 50 ppm Borates can not only help control pH, but can somewhat control algae. However, adding that now and then later diluting the water to lower the CYA will require adding more Borates again later. Also, it's a challenge to add Borates to the pool when the pH isn't already where you want it. Another approach that can somewhat inhibit the algae growth (though will not clear the pool of algae) is to use a phosphate remover, but that will get very expensive if the phosphate levels are high and it will temporarily cause severe cloudiness of the pool (some phosphate remover products have a clarifier built-in for that reason). Obviously this is a stop-gap measure and is not the recommended solution because it does not address the fundamental high-CYA problem. There are other algae-killing choices, but have other side effects, such as copper that can lead to staining so I'd stay away from that (though with a black finish pool I wonder what such staining would look like).

Thanks I was wondering why some pools the pH locked in at difference TA's. I think I remember Chem mentioning this at sometime. What I've been doing is lowering pH in my pools and over time the TA gets to a point where the pH gets locked and I don't have to add acid anymore.

Yes there are those other methods of treating algae but I prefer to stay away from those and do the FC/CYA method which works very well. Borates is good but something like adding icing to a cake most homeowners would not pay for it and I havent added that to my service. Will do in the future though. However my clients pools are like glass so clear you don't notice the water unless the jets are pushing it so it is hard to get them into adding borates as they are very happy.

There is a small waterfall in this pool and it is outside and uncovered. I retest monday. I probably need to give it another good shock to finish off the last bit of CC. will see.

The other pool I have also has high CYA of 290 but keeping FC at 15-17ppm has worked well and no complaints. Owner loves the pool water and doesn't smell any chlorine. However when I first took over I thought CYA was 150 so lowered FC down to 7.5ppm but then owner smelt some chlorine residue on her skin so I raised it back up and no more complaints.

definitely don't want copper in my pools. I also only recommend heat pumps with titanium cores. I stay way clear of copper or anything else like that.

 

[Aquatica]

just heard from my client and the water is still smelling of chlorine.

Looks like I have to shock once more. just hope she doesn't tie my hands and lets me just do my job. I have to shock.

 

[Aquatica]

got rid of princess. she would not replace water and really insulted me. I have no time for those clients. she is fired.

moving on..

 

[Guest]

Gallon of chlorine: $3.00. Gallon of acid: $4.00. Gas to get to the job: $3.50. Firing the princess: Priceless

That is classic! I'll have to remember that we can fire our accounts if we don't like them! I love it!!

 

[PoolGuyNJ]

Been there, done that. You can lead a horse to water but you can't make them drink. It's why I point my customers here.

Scott

 

[Aquatica]

yep a very impossible to deal with client.

gave her back her money for the swg and we are removing it tomorrow morning. I need to see these types coming. this is what I have learnt from this experience. I will have to be more careful in future.