Algae & Water loss problems

[bethalito]

Hi All;
Glad to have joined up to the TFP club! I have had a pretty trouble free summer with the pool, but the last month has been algae nightmare!
The specs:
27k; Hayward Sand Filter; IG; Plaster; 1 hp pump; 98 gpm flow rate.
Test Results using TF-100 kit:
10/12:
FC 10.5
CC: 0
PH:7.3
TA:70
CH:220
CYA:60
Temp:58

The algae problem appeared about a month ago. Started very green. Currently, very pale green with yellowish residue on bottom & sides. I hit it with algecide like the pool store said about 3 weeks ago. I have been brushing it one day & vacuuming the next. Backwash once a day. Running the filter 24-7. I can see the FC is very high & don't know if I need to add more. I was using shock. I want to switch to the BBB method. Should I just keep scrubbing & vacuuming or are there other steps I can take to stop this! I want to shut it down for the winter.

The leak problem:
The spider gasket in the filter has been replaced twice this year. I haven't called the guy back to fix this last one yet as I have been pre-occupied with the algae. I have a mason-jar cap in the backwash line to stop the water from leaking out. Works pretty good. I take it out when I need to backwash. If it wasn't there, we would be losing water like crazy. We've owned this pool for 5 years & haven't had this problem before. Pool guy said there is another gasket in there that may need to be replaced if replacing the spider gasket didn't work. Anyone have any ideas?

The other thing about this pool is it doesn't get full day sun & there are quite a few fir trees around it. Makes for a lot of cleaning!

Thanks!

 

[PoolGuyNJ]

If running the filter isn't clearing the water, it's because the brushing and decomposing algae have formed very tiny particles that the filter can't get. Flock it and vacuum to waste. You'll be done in 24 hrs.

Scott

 

[bethalito]

Thanks! What does "flock it" mean?
Vacuuming to waste will be purging the water from the pool, correct? How long to I let it go to waste? 1 min, 5min, 30 min?

 

[teapot]

98 gpm flow rate.
The leak problem:

That may be the problem, you are not filtering out anything but the sand in the filter will be clean :lol:

What size is the filter/s?

 

[bk406]

Currently, very pale green with yellowish residue on bottom & sides. I hit it with algecide like the pool store said about 3 weeks ago. I have been brushing it one day & vacuuming the next. Backwash once a day. Running the filter 24-7. I can see the FC is very high & don't know if I need to add more. I was using shock. I want to switch to the BBB method. Should I just keep scrubbing & vacuuming or are there other steps I can take to stop this! I want to shut it down for the winter.

Your problem isnt anything but lack of chlorine. Your CYA level is 60. That means your shock level is around 24 ppm of free chlorine. Running the filter 24/7 is what you need to do, but you are at about half of the shock level for your CYA. It will never clear unless you raise the chlorine to 24 and HOLD it there until
1) the water is clear
2) the overnight chlorine loss is less than 0.5-1 ppm
3) The CC is less than or equal to 0.5


At this point, floc will do no good. You have to properly shock your pool. You said you used shock, but what did you actually add? Powder? Liquid? Shock is really not a product, but a process. You should really use liquid chlorine (aka bleach) at this point to shock the pool. Read the articles in pool school on how to shock your pool. If you follow the proceedure, your pool will clear.

 

[PoolGuyNJ]

The FC of 12, even with the CYA at 60, is enough to have killed the algae. The brushing threw it in suspension. He can filter for a week and it won't clear, regardless of the FC level. High FC doesn't clear it. Floc will cause it to drop out to the floor. One vac to waste session will remove it.

Scott

 

[bk406]

He says his pool is still green. He is no where near shock level for his CYA. Shock level for a CYA of 60 is 24, not 12.
Do you discount and not believe the FC/CYA chart?

 

[PoolGuyNJ]

Shock level isn't usually needed to kill algae, just to get rid CC or break down/oxidize waste. Takes too long. Heavy blooms that have been brushed put a lot of fine crud in suspension. When it's been more than a couple days and the water isn't cleared by the filter after 8 or 10 turns, knocking it back down to the floor and a vac to waste and it's done with.

It's not like floc is that costly. Electricity for the pump costs too.

Scott

 

[dmanb2b]

Shock level isn't usually needed to kill algae, just to get rid CC or break down/oxidize waste. Takes too long. Heavy blooms that have been brushed put a lot of fine crud in suspension. When it's been more than a couple days and the water isn't cleared by the filter after 8 or 10 turns, knocking it back down to the floor and a vac to waste and it's done with.

It's not like floc is that costly. Electricity for the pump costs too.

Scott

Scott, I hear you but before the the OP starts spending $ on floc, we should confirm they are done shocking. If they are still losing FC overnight the algae will come back and the pool will stay green, regardless if you add floc or not. Let's make sure the algae is dead 1st. You are jumping to the next step without confirming step 1 is done.

 

[bk406]

Shock level isn't usually needed to kill algae,

Thats contrary to what has been documented on this site. I'm sure Chemgeek could shed light on this. If lower levels of chlorine were needed to kill algea, im sure the FC/CYA chart would be altered. And, as you are aware i'm sure, an algea bloom does not necessarily come with elevated CC levels.

 

[teapot]

Looks like the OP has gone walkabout so not much point in doing or saying anything untill they return. I still want to hear more about filtering at 98 gpm

 

[bethalito]

Hi all, sorry, been at work for 10 hr shifts since I last wrote.
OK, I used 7 lbs of sodium dichloro-s-triazinetrione dihydrate the last time I shocked it & that was a while ago. Saturday 10/16, the pool was vac'd & scrubbed. Filter was back washed & then water was sent to waste. Before that was done, you could see the bottom on the deep end. There was slight growth on the walls & there was sediment on the bottom. Now that it has been cleaned & scrubbed, you can't see the bottom on the deep end.
Here's my plan. I am going to add liquid bleach to the pool. Using the pool calculator, that comes out to 4 1/3 182oz size containers of 6% bleach. Scrub it, test it daily & see what happens in the next couple days. I think I am almost there, but it should not have taken this long. Not using enough chlorine & not jumping on it fast enought were the 2 main problems. I will report back! Thanks!

 

[bk406]

Sounds like you have it down. The key is to keep the pool at shock level as best you can and not let the FC fall too far below that for too long. It is tough to do when your not home during the day. But, testing in the morning and when you get home and adding bleach to keep the FC at 24 ppm, or close to it, will clear your pool. Be sure to use liquid as you are now aware. Using dichlor just increases the CYA and makes it that much more difficult to shock since you actually add more CYA in the process. Leave the filter running 24/7 to filter the dead algea.

 

[chem geek]

Shock level isn't usually needed to kill algae,

Thats contrary to what has been documented on this site. I'm sure Chemgeek could shed light on this. If lower levels of chlorine were needed to kill algea, im sure the FC/CYA chart would be altered. And, as you are aware i'm sure, an algea bloom does not necessarily come with elevated CC levels.

The shock level kills algae more quickly for a faster clearing and it ensures that if there are clumps that the chlorine breaks through them faster to get to algae that may still be growing. If the algae is fairly light and dispersed, then anything above the minimum FC/CYA levels should kill it faster than it can grow, but that's really being on the edge and will take a long time to clear and one must add chlorine very frequently since it will usually get used up quickly.

So one has options. If one wants to use supplemental products (clarifiers or flocculants) at extra cost to usually (but not always) speed things up, that's up to them, but it's not usually necessary for pool homeowners (but might be more useful for pool services that need to clear things up faster since they're getting paid to do so). This thread shows a pool with algae (upon opening) getting cleared using chlorine alone, though there was some vacuum-to-waste after the algae settled so this took around 4 days overall.

 

[teapot]

Leave the filter running 24/7 to filter the dead algea.

I would still like to hear about filtering at 98gpm as I am sure that won't filter very much at all. That is a high flow rate even for backwashing the filter. What ever happened to 30gpm? That may also explain the frequency of the replacement spider gaskets

 

[bethalito]

Hmmm, all good responses! Chlorine is in, pool is brushed, pump is on 24/7. Question: How do I check for FC of 24 if my little tester tube only goes up to 10? After I added the powder chlorine ( a while back), the color was almost orange. PH is still good. Hi, ho, hi ho, brushing as we go.
The sand filter is a Hayward S-210T

 

[bk406]

How do I check for FC of 24 if my little tester tube only goes up to 10? After I added the powder chlorine ( a while back), the color was almost orange.

I thought you had a TF-100 kit? You should be using the FAS-DPD test for FC.

 

[teapot]

Hmmm, all good responses! Chlorine is in, pool is brushed, pump is on 24/7. Question: How do I check for FC of 24 if my little tester tube only goes up to 10? After I added the powder chlorine ( a while back), the color was almost orange. PH is still good. Hi, ho, hi ho, brushing as we go.
The sand filter is a Hayward S-210T

From the information I have, the maximum flow rate for your filter is 45gpm but remember the slower you filter the better so 30gpm will give a much better filtration performance.

 

[bethalito]

Tested yesterday & using the FAS/DPD test came up with a FC of 18. Added another gallon of bleach (182 oz).
PH: 7.8. I'm thinking of adding muriatic acid to bring it down to 7.5? Does that sound correct?
T/A: 80
CH: 220
CYA: 90~up from 60, but it may be that I am new to testing.
Temp:a balmy 54F.
It is looking better. Not completely clear yet, but 95%. Vac & scrubbing diligently.

Thanks all!

 

[duraleigh]

Disregard your pH result and do not add any acid.

In the presence of high chlorine, the pH test will read falsely high. You should not have to readjust pH until your pool is clear, the shock process is complete, and you have allowed the FC to go back below 10ppm.

The CYA test is frequently hard to do when you first start. The CYA itself should not vary in your pool significantly unless you change it. I would suggest you retest again to get a better idea. It is helpful to perform the test using the same sample over and over. Simply pour it back into the squeeze bottle from the view tube and then back into the view tube again. It'll help you get an "average" reading.