Cannot get rid of the algae !!

[jenner]

This is in response to Chemgeek's query at to my fill water being high in TA.
Just tested my tap water, which is what I top up/refill my pool with and the TA test shows TA at 100. This is pretty average isn't it?. However, whenever I have topped up my pool during the summer the TA level goes up in the pool and I lower it with Muriatic acid.

Thank you for all your help. The algae is definitely clearing and the pool is much clearer but with the CYA so high I'm always going to be battling unless I use very high dosages of chlorine. So I am now intending to half to three quarters drain the pool. We don't get enough rains here in California to make a real difference (unless you count the ones we got in 2003)

I'll let you know how I get on

[chem geek]

This is in response to Chemgeek's query at to my fill water being high in TA.
Just tested my tap water, which is what I top up/refill my pool with and the TA test shows TA at 100. This is pretty average isn't it?. However, whenever I have topped up my pool during the summer the TA level goes up in the pool and I lower it with Muriatic acid.

Actually, with fill water that has any significant amount of TA, and 100 is significant though not huge, you will increase your TA over time IF your pool water evaporates and you fill with new water that contains any TA in it. So it is quite possible that if you are filling up due to evaporation that your TA will increase (assuming your pH remains constant). The other way that TA will increase is if the pH rises over time, but adding acid will lower both the pH and the TA. I suspect there might be a little bit of both going on. Only if you splash out water or backwash a filter and then refill would I expect the TA to slightly go down rather than up. When you do the drain and refill to reduce CYA, you will find that your TA will go down towards the 100 of the fill water.

Thanks for giving me more details. And congratulations on your pool clearing up -- it's on its way so as Carl says, Patience, Patience, Patience.

Richard