Pressure just builds......

[duraleigh]

You must get rid of the algae in your pool. Almost surely your filter is being clogged because of the algae.

Post a set of test results (FC, TC, pH, Alk, CYA) and you'll get lots of good help.

[waste]

AJ, welcome to the forum. I'm almost positive that Dave is correct in his assesment, algae will clog a de filter very quickly (the reason being that individual algae cells are ~the same size as the filtering channels in the de). However, the grids may have accumulated oils or calcium build up over the course of 7 years, in which case a TSP bath and an acid bath may be in order.
Do you have sufficient water, both in the pool and available to refill the pool, to do your vacuuming to WASTE ?(no relation to me) As Dave said, getting rid of the algae should be your priority. If you need any help with the algae removal, take a look at the "Dealing with algae" section of this forum. Good luck and keep us posted - should you need any more help, just ask, some of us live for this stuff

[ajwray]

Thanks,

I thought it might be algae as well at first but I'm not so sure now. When I opened I put in 5gal 12.5% brushed the sides, vacumed to waste, then opened the filter, cleaned the grids. Works for two hours. Next day repeated the above minus the 5gal. Works for two hours. Next day another 5 gal vacum to waste, clean the grids (which were not green at all) and then worked for two hours. Daily after that cleaned the grids, let run.

Algae was my first thought as well but it's never taken this long to clear in the past, (first time when we bought it and another when the squirrels ate through the cover). I am on my way to the local pool store to get some fresh chemicals for my testing kit and will post those asap.

I have been around this forum for a while but this really is the first time I have had problems, the help in a friendly manner that everyone gave is really appreciated.

[ajwray]

CYA 36
TC 3
FC 3
PH 8.2
TA 109
HARD 140

Realize I have to bring the PH down. I am also going to chemically strip the filter today.

Any other suggestions??

[waste]

Use a detergent or TSP to get the oils off before acid washing the grids.

[ajwray]

Waste...thanks for the advice. It's soaking right now in TSP overnight. In the morning I will rinse well and then do the acid.

[ajwray]

Status Update: The water is almost totally clear but the grids still only go about three hours then I backwash and they need another three hours. Then backwash. I did the TSP soak overnight. Then the acid soak overnight. Vacumed to waste. Current test results:

TC 3
FC 3
PH 7.6
TA 109
CYA 36


20k gallon 16x32


Any other suggestions? Maybe time for new grids (they look fine)? The suction and return lines are fine because the pressue is even when on recirculate.

Help!! I'm selling this house in two weeks and don't want to spend too much more money for a pool I'm not going to enjoy.