Phosphate battle

[proximo]

I'm a new pool owner.

Our house has well water which is a blessing but now I'm finding also a curse. The well water is high in phosphates so each time I add water to refill after evaporation (around 45min a day) I'm adding phosphates to the water. Needless to say we've dealt with several algae problems especially horrible mustard algae. I have used several products to help reduce the phosphate level including Natural Chemistry's Phos Free. This worked pretty well but I could never get the level down below ~200. Right now the reading is about 500-700. I feel like it's a losing battle with having to constantly add well water to the pool.

My question is should I be so concerned with this reading? I know phosphates feed algae and I don't want to do that. If I should are there other products/methods I should try? Also would converting to a salt generator help solve the problem with algae growth? I have read the FAQ about adding Borax and I will try that soon.

Thanks in advance for any help!

[aylad]

You need to stop worrying about the phosphates and start battling the algae instead. Phosphates are algae food, but if there is no algae, then your phosphate level doesn't matter! Your algae problems are probably because you simply haven't been consistent about keeping your chlorine levels high enough to compensate for your CYA level. If you will post a set of test results on your water, taken with a drop-based kit, we can help you get it cleared up....

Welcome to the forum!

[proximo]

Thanks for the direction and welcome! Here are my test results:
Chlorine - 3.0
PH - 7.6
TA - 120

I have recently been reducing ph and TA with muriatic acid. Water is cloudy from dead algae. Also have been shocking the pool and brushing the sides and bottom.

Do I ever need to reduce phosphates?

[waterbear]

NO, phosphates are a non issue. What you DO need to do is get a good test kit (Tayloe K-2006) and you need to test for free chlorine, combined chlorine, pH, total alkalinity, calcium hardness AND CYA (stabilzier or cyanuric acid). This last one is one of the most imortant tests and the one most often not done! Without it you do not know how high you need to keep the chlorine to keep the algae away.

[proximo]

OK thanks! I just ordered the test kit you had recommended with your Amazon link.

[PoolDoc]

Another note . . . phosphate removers can probably remove phosphates down to any low level you can measure at pool side, and such low phosphate levels will inhibit (not totally prevent) algae. However, what pool stores don't tell you is that many common pool chemicals CONTAIN phosphates! We've had several pool store 'prescriptions' posted this year which contained BOTH phosphate removers AND phosphate based, or phosphate containing, products.

Given your persistent upward trend on phosphate levels, I'd wonder just what ELSE your pool store is selling you. It's quite likely they are 'helping' you remove phosphates on the one hand, and then 'helping' you add them back* on the other! If you want to know, you'll need to list the EXACT product names of everything you've added since the last low phosphate reading.

Ben


* To be fair, the only thing about pool chemistry most pool store operators know is what they are told by pool chemicals companies, and, as you might imagine, this little titbit is not usually part of such training!

[kelemvor]

each time I add water to refill after evaporation (around 45min a day)

Does your well flow very slowly? That sounds like a lot of water to be adding every day. If it really is evaporation, you may want to invest in a solar cover once you get the chemicals and algae under control.

[proximo]

Thank you for all the input! I'm very excited to have all this collective help.

I received my Taylor k-2006 test kit. Wow! What a change - I feel like a mad scientist with all these tests! (evil cackle off in the distance). Anyway here are my results:
FC: 23ppm
CC: 0
PH: 7.2
CYA: 60
TA: 170
CH: 80
Saturation Index: -.45

The FC may be extra high as I just shocked it for the second day in a row the previous night. I used the no-brand 6% chlorine for the first time. The water is clearing up but is still cloudy. I will shock it again tonight. Also I've been steadily trying to lower the PH - it's typically around 7.8 or higher. I'm planning to add the Borax soon to help inhibit algae. Any advise would be greatly appreciated!!!

@kelemvor Our well is pretty slow. I never had to add water in the winter or early spring. I also did a bucket test to see if it was a leak. The water is very warm (East Texas) - around 88-90° right now.

@PoolDoc - I have over the course of the last year added a few algaecides, flocs, pool clarifiers and other expensive junk. I would not be at all surprised that I've worked against the Phosphate removers I was using. The main problem I had with the phosphate removers is that my sand filter would get so clogged up with it that I had to keep backwashing it to keep it running normally. In addition the previous owners were sold an oversized 1.5hp pump - so it's laboring extra hard already. I plan to reduce this to 1hp when it gives out.

Thank you for all the help! It's truly appreciated.

[waterbear]

Before you add the borax and acid for the algastatic effect of borate at 50 ppm work on getting the TA down a bit. Your high TA is why your pH is always on the high side. Here is the reason (warning, it is geeky chemistry stuff):
High TA means a high level of bicarbonate in the water (bicarbonate is the main thing we are measuring when we measure TA--this part of TA is also called "carbonate hardness" or "carbonate alkalinity" or "kH" in water testing other than pool/spa water testing.)
The higher the bicarbonate the faster carbon dioxide will outgas from the water (because at normal pool pH range we have a buffer system of bicarbonate and carbonic acid in the water and carbonic acid is, for our purposes, carbon dioxide dissolved in water, and the higher the bicarbonate level the higher the carbonic acid level to balance it).
Out gassing of CO2 is the main cause of pH rise in a pool (not counting curing new plaster). I hope I have not confused you with this introduction actual chemistry of what is going on! The main point is that if your TA is high your pH is going to rise fast and toward 8.3 and the cure is to lower the TA to slow the pH rise.

At any rate, before adding the borax and acid work on getting the TA down to about 100-120 ppm if you are planning on continued use of your trichlor feeder or to about 70-90 ppm if you are switching to bleach as your main chlorine source (probably a good idea with CYA at 60 ppm!)

Lowering TA is a process so when you are ready for it let us know and we can walk you through it. In the meantime you can read up on it.

[proximo]

Thanks for the help, waterbear. I assume regular doses of muriatic acid are the best way to do this? I have been adding a pint or two in the morning and evening. Is there any danger of getting the PH too low before we hit the target TA range?

Does the use of trichlor tabs contribute to too high TA levels? If I stop using the chlorine feeder will I just have to add bleach every day?