I think it is the tank and not algae

We have been battling dead algae on the bottom of the pool since we opened it in May. We have vacuumed to waste numerous times, but the stuff returns the next morning when we restart the filtration system (above ground pool). The local pool store said my chlorine was very low and I really super shocked it this weekend. My water is crystal clear (and has been all season), but the dead algae was still on the bottom of the pool. So, once again we vacuumed to waste and the stuff has reappeared within hours. Could it be the valve control thing on top of my tank? That is the only other thing I think it could be - that somehow the algae is still dropping back into the tank and not actually being sucked out. We have noticed this year that when backwashing, we don't have near the pressure we had last year and the water has yet to come out dirty - all season. However, when using the rinse function, it occasionally runs dirty. In the past, we would backwash once per week and the water would run dirty for a few minutes.

Someone please help. I'm at my wit's end and my water bill is through the roof. We have dealt with dead algae in the past and one vacuuming to waste took care of it. We have been vacuuming to waste for two months to no avail.

Thanks,

Kim

Kim:
Please read the stickied threads at the top of the "Pool Chemicals and Pool Water Problems" topic,
the "Using Chlorine and Chlorinating Chemicals" topic
and the
"Testing and Adjusting Pool Water Chemistry" topic.

The do a search for threads on battling algae.

That will save me a lot of typing.

My specific question is about the filter - not algae. Could there be something wrong with the valve that is causing debris to go back into the pool even on waste and why is my backwashing not as strong as it used to be?

I forgot to add that the stuff reappears within minutes sometimes. I think I have a filter problem and would like some opinions before I go spend major $$ on a replacement part.

What is a spider gasket - what does it do and do I possibly need one? All sand was replaced about a month ago and all the laterals thoroughly cleaned. The sand had a layer of grayish gunk on it that would not backwash out - all backwashing this year has been clear which I find very strange.

The 6-way valve has a bunch of chambers in it to direct the water in various directions. To seal those chambers there's a cover (on the bottom of the valve) and between that cover and the valve is the rubber spider gasket--so-called because it looks like a simple spider's web. You want to use plenty of silicon gasket lube on it when you install it.

Thank you Carl! So, it is possible that the problem lies in the filtration system then. Will this cause the backwashing problem I described also? Is my water just recirculating and not filtering? What is happening to the stuff I'm vacuuming to waste - my pool is draining when we do this, but my only guess now is that somehow the dirt/algae is getting back into the pool rather than flowing out with the water. Am I on the right track?

Again, thanks so much for the help. All I have heard from the pool store is that I have algae in my water. Possibly, but if that much algae was dying out and dropping to the bottom within minutes I don't think my water would be sparkling clear.

Kim,

In "waste" position, NO water should reenter the pool. Can you not verify that by placing your hand over the return eyeballs? There is no other reentry point for the water other than the returns.

Can you see the water exiting the pool in the "waste" position?

Hi Dave,

Yes, water is exiting the pool, but within minutes some of the stuff is back on the bottom of the pool. We can vacuum to waste and see some stuff reappear immediately. Then, if we shut the filter down and restart it a few hours later, it looks like it all reappears around the outer edge of the pool (in the line of circulation). The backwash thing has me stumped too. In the past the water would come out with a lot of force during backwashing and there would always be some dirty water come out weekly. Not this year - we have about half of the pressure when backwashing and absolutely no dirty water coming out. A couple of years ago we had a huge algae bloom after a heavy rain and the water was totally green. We shocked and cleared it up and vacuumed the dead algae to waste one time. One time was all it took. My water has been clear all year. This stuff was on the bottom when we took the cover off in May and we still can't get it out. There is absolutely no slimy feeling anywhere in the pool and the water is clear. That is why I think it has to be the filtration system.

Thanks!

I suspect the filter as well but your answer is not clear to me. Let's try it another way.

If you put the filter in "waste" or "backwash" position and turn on the pump, can you feel or see water going back into the pool?

Oh my, I feel like such an idiot! Dave, I just went out to check, and yes - on waste I can feel a lot of pressure coming back into the pool. There is some on backwash, but not as much. Duh, why didn't I simply stick my hand in front of the return jet two months ago????? We couldn't see any water coming back in, or at least didn't notice it.

So, what to do to fix this? Is it a spider gasket? My tank is just 2 or 3 years old.

Thanks so much!