I have a 2 and 1/2 year old fibreglass pool which has a white scale when it dries. When wet it is hard to see. If I drop the pool level a solid white deposit is seen when the water dries.
This may or may not be a coincidence but it appeared after I put a Sparkle Pill in the pool a day ago. Ran the pump per the instructions, it went in at around 2pm and when I got up the following morning I noticed a white 15mm (nout 3/4") mark just above the pool line. Thought it would just wash off with a dense sponge but no joy. The Sparkle Pill contained Alumina Salt which is a floculate.
I contacted the manufacturer of the Sparkle Pill who basically said that no way would the pill cause the issue! It wasn't there before I put it in and no other chemicals were put in. So I have just assumed it has something to do with the Sparkle pill.
I then proceeded to use on a test section some Bi Carb of Soda no joy, then tried car cut and polish no joy what so ever when the section dried the white deposit showed as before. The fibreglass gel surface from the water line down feels course not smooth as is the case above the water line.
Anyway I got our local pool shop guy around and he tested the water as his thinking was a high level of calcium, results were vitually no calcium detected and the Ph was low but all agreed that it would cause this issue. A couple of handfulls of Ph buffer and the pool is in perfect balance. On close eximination with the pump switched off and pool perfectly still if you look down the sides you can just see a slightly uneven deposit of something on the walls. When the deposit is wet it is hard to see .....when it dries it is white and very prominant.
I then proceeded to use on a test section Bi Carb of Soda, car cut and polish no joy what so ever when the section dried the white deposit showed as before. At this stage I rang our local pool shop for assistance.
The pool shop guy has hit a test patch with everything he had. Multi stain remover, some other stain removers and after consultation with the pool manufacturer we tried at his suggestions some citric acid (no joy) then 50/50 Hydrochloric Acid/water (no joy) then fully concentrated Hydrochloric Acid and still no joy. Nothing used reduced or removed the deposit.
I have read here and in other forums that metals can be attracted to fibreglass pools. Unfortunately the description
For the moment I have the water about 50mm above the water line ensuring that the deposit remains wet and I don't have extended periods where the deposits remain dry on the fibreglass.
We still are not sure what the deposit is, obviously if that was known then the corrective action is probably the easy part. I am hoping that some one might have some suggestions as to what it might be and what might a solution to correcting the problem. I would appreciate any thoughts, comments and suggestions.