Maybe a unique problem you all might be interested in

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njneer75

njneer75

0
Aug 9, 2017
17
Sunrise, FL
I bought a house this year in Feb that came with a very unique pool design and circulation system. Probably some of you older members may remember this from the 80's. Its in South Florida, close to the Everglades out west, on the end of a lake, and gets constant rain and breeze. The pool was built in the 80's and is a double kidney free form fiberglass pool. Yes it does need to be refinished but I dont have that option right now. The pool has that old school "self-cleaning" filtration system built into the bottom. So six holes that constantly bubble the return flow from the filter. The "cleaning" heads have thus disintegrated over the years and I cant find replacements. So I essentially have a huge hot tub! It looks really cool but Im starting to think that the constant rain, breeze, and aeration, are causing me an algae nightmare. I have been taking care of pools since the 70's as a kid and have never experienced the issues Im having with this pool.

Pool1 - Album on Imgurpool2.jpg

My free chlorine gets eaten up almost every 3 days. These are the numbers Ive been using:
FC=4.0
CYA=70
PH=7.5
CH=350
TA=90

TA, PH, CH, and CYA remain pretty much constant with little fluctuation. Ive shocked the living heck out of this pool several times over the last few months but still get a buildup of mustard algae after every third or fourth day. The house is a remodel so Im not living in it yet and due to work, can only make it there on my two days off every week. So my question is this. Bad fiberglass surface holding algae, physical conditions of the atmosphere, or the crappy filtration system? Or, am I way off on my chemical treatment? Please be kind, its my first post in this forum.
 
Are you saying there is no sand, cartridge, or DE filter at all?

I'd assume you don't have a salt water pool since you'd probably would have mentioned that in your post. As such 70ppm CYA is a little high and it sounds like you have algae hidden somewhere so one way or another you're probably looking at needing to SLAM the pool.

I'm interested in knowing more this filtration system, I'm wondering if there are areas in it that could be hiding some algae.
 
Hi and thanks for replying. Here is a link to another post I made with more detailed info about the pump system (Need advice on new plumbing and pool remodel). CYA is high, yes. But here in South Florida where the temps get up to 100 degrees, and the direct sunlight on the pool can be 8-10 hours a day, you kinda need a bit more CYA than in most other places in the country. It forces us to keep chlorine high but its the price we pay. Ive found that CYA levels under 60 will cause chlorine to get eaten up hourly. So a little higher CYA and little higher FC usually means stability. However, this problem I am having with the algae is different than Ive ever experienced before. Thats why I came here. Looking for anyone else in my area that has experienced the same issue. I honestly think the algae is hiding in the recesses of the disintegrated fiberglass finish but Im no expert.
 
With a CYA of 70 your FC is about 1/2 of what it should be assuming no SWCG. Use liquid chlorine (bleach) to get that up around 8 and make sure it never drops below 5. That should help but to completely get rid of it, you are going to have to follow the SLAM process.
 
pabeader said:
With a CYA of 70 your FC is about 1/2 of what it should be assuming no SWCG. Use liquid chlorine (bleach) to get that up around 8 and make sure it never drops below 5. That should help but to completely get rid of it, you are going to have to follow the SLAM process.
Click to expand...
+1. Your FC is too low.

[FC/CYA][/FC/CYA]

You say that your FC gets eaten up in 3 days... how many ppm do you lose over the 3 days? It is normal to lose 2-4ppm a day. Two major factors to FC loss are sunlight & organics. Can the pool pass an Overnight Chlorine Loss Test? If no, then it's time for a SLAM Process. You already have the correct test kit, just make sure you have enough FC reagents so you don't run out in the middle of the SLAM.
 
Generally I was trying to keep the FC at 4-5ppm. This will normally get eaten up within 3-4 days if I am not at the house to keep topping it off. Since I am not living there right now, I will put enough chlorine in the pool the night before I start my work week and jack it up to 6-8ppm so at least it gives the pool a fighting chance until I return at the end of my work week. I know this is not an ideal situation, but its my only option for now. I will try the OCLT tonight and post results. If needed, I guess I will need to SLAM. I have the week off work so I can work on the house and pool.

One more issue I forgot to mention in my original post The circulation system has two 1/2" ball valves that control the suction independently from the skimmer and the deep end bottom drain. The ball valve controlling the deep end drain has broken in the off position so Im only getting filtration through my skimmer. Is this an issue? Thanks
 
domct203 said:
+1. Your FC is too low.

[FC/CYA][/FC/CYA]

You say that your FC gets eaten up in 3 days... how many ppm do you lose over the 3 days? It is normal to lose 2-4ppm a day. Two major factors to FC loss are sunlight & organics. Can the pool pass an Overnight Chlorine Loss Test? If no, then it's time for a SLAM Process. You already have the correct test kit, just make sure you have enough FC reagents so you don't run out in the middle of the SLAM.
Click to expand...

I've performed an OCLT with a result of 1.0ppm loss. I think I am going to drain some water, try and get my CYA to 50ppm, then do a SLAM. 1.0 is right a the high end of acceptable for a SLAM I see.
 
Jezza said:
A loss of 1 FC or less is a pass for an OCLT. Does the water look clear?
Click to expand...

Yes the water appears very clear and blue....for now. I dont mind spending a little on chlorine to do a SLAM just to ease my mind. Im on off work for a few days and working on the house so I can monitor the pool.

- - - Updated - - -

One more issue I forgot to mention in my original post The circulation system has two 1/2" ball valves that control the suction independently from the skimmer and the deep end bottom drain. The ball valve controlling the deep end drain has broken in the off position so Im only getting filtration through my skimmer. Is this an issue? Thanks

 

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That's good! You only really need a skimmer. Main drain is nice but not necessary.

Brushing each week is a good idea.
 
Thanks for all the help so far. Seems like most everyone agrees FC being kept to low. But here's what Im trying to accomplish and tell me if Im way off please. Since I cant tinker with the FC every day and can only add chlorine to the pool on my two days off for the week for now, does keeping CYA and FC high make sense for extreme south florida weather? If my stabilizer is high anf the FC is high, by the time I return to the pool on day 6, or end of day 5, pool should be swimmable and clean? Or, does this process lend itself to enticing an algae bloom once my FC drops after 3rd or 4th day in? I refuse to higher a pool service. Cant trust people down here to do the right thing anymore.
 
njneer75 said:
Thanks for all the help so far. Seems like most everyone agrees FC being kept to low. But here's what Im trying to accomplish and tell me if Im way off please. Since I cant tinker with the FC every day and can only add chlorine to the pool on my two days off for the week for now, does keeping CYA and FC high make sense for extreme south florida weather? If my stabilizer is high anf the FC is high, by the time I return to the pool on day 6, or end of day 5, pool should be swimmable and clean? Or, does this process lend itself to enticing an algae bloom once my FC drops after 3rd or 4th day in? I refuse to higher a pool service. Cant trust people down here to do the right thing anymore.
Click to expand...

Your CYA level should be high enough to reduce the effects of sunlight, but not too high that you will need a truckload of bleach to sanitize the pool. Your FC needs to always remain above 7.5% of your CYA to prevent algae. That 7.5% is with ideal conditions, and everyone's pool is different. With my pool I find that a 10% minimum works best to keep the water TFP crystal clear and free of algae.

You could try raising your FC to shock level (40% of CYA) and see if that keeps your FC above minimum when you return, but in the long run this is a very expensive and inefficient way to manage sanitation.

So, with a CYA of 70ppm, shock FC level is 28ppm, minimum is 5.5ppm. That is a 22.5ppm 'range'. The higher you are above your daily FC target, the faster FC is depleted by sunlight. You could very well lose 12-15ppm in the first two to three days, then 3-4ppm each day after. By day 5 or 6 your FC will most likely drop below your safe minimum. This is assuming perfect conditions, and a good storm or two during the week could make matters worse.

Your best bet here is either a SWG, or chlorine injection system.
 
domct203 said:
Your CYA level should be high enough to reduce the effects of sunlight, but not too high that you will need a truckload of bleach to sanitize the pool. Your FC needs to always remain above 7.5% of your CYA to prevent algae. That 7.5% is with ideal conditions, and everyone's pool is different. With my pool I find that a 10% minimum works best to keep the water TFP crystal clear and free of algae.

You could try raising your FC to shock level (40% of CYA) and see if that keeps your FC above minimum when you return, but in the long run this is a very expensive and inefficient way to manage sanitation.

So, with a CYA of 70ppm, shock FC level is 28ppm, minimum is 5.5ppm. That is a 22.5ppm 'range'. The higher you are above your daily FC target, the faster FC is depleted by sunlight. You could very well lose 12-15ppm in the first two to three days, then 3-4ppm each day after. By day 5 or 6 your FC will most likely drop below your safe minimum. This is assuming perfect conditions, and a good storm or two during the week could make matters worse.

Your best bet here is either a SWG, or chlorine injection system.
Click to expand...


Omg thats a lot of math haha. Seriously though, your reply got me thinking about a swg. Since the house is a remodel, my only care is that I dont want to pass on any problems to the next owner (yes I have morals). Its so crazy here in SoFlo how fast chroline gets eatied up in pools. I rarely mess with Ph, Ch, Ta, Cya but darnit the bleach!
 

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