Pump weakens when vacuming

[Coach]

Hi all, my pool is only 1 year old and started having this problem last year, it will run fine while operating normally, backwashing or vacuuming to waste. When I vacuum to the filter my pressure goes up to around 20 and I lose all my suction. I have taken it apart and the impeller is clear so I'm not sure what the problem is. Thanks in advance.

[Watermom]

Hey, Coach! Welcome to our forum!

Asking the obvious, but have you backwashed recently?

[Coach]

Yup, I have backwashed the heck out of it, when it stops working totally, I backwash it and it starts working again. But if I try to vacuum it just shuts down again. By the way, I know this sounds dumb by me not knowing for sure but I think it is a DE filter, I'm not sure I bought the whole thing used from someone but he had never put the pool up.

[Watermom]

I'm gonna ask Al to take a look at this problem to see if he has any ideas to help you.

[Poconos]

Welcome to the forum. First you have to confirm that it is a DE filter. I never dealt with them but I do know that after you backwash you need to add more DE. In your case the fikter looks plugged in the filter direction. I think I remember that if you run them without DE powder then you run the risk of damaging the grids or membranes. Could be plugged in one direction with the crud you vacuumed. I'm making an educated guess on the previous comments. Someone else will know for sure and also suggest how to clean them. Would be helpful to have the pump info too. That will give an very rough indication of the max pressure you can hit with fully blocked flow. I'm wondering how close that 20 psi number is to the blocked pressure.
Hope this helps a little.
Al

[Coach]

Ok, I did open up the top and I looked in the filter, it looks like sand with some stuff in it, I'm still not sure which it is though. So do I just go buy a bag of DE and add some?

[Watermom]

DE looks like baby powder. You ought to be able to tell if it is DE. Do you have the manual that goes with the filter and if not, can you do a search (brand and model) online to see if you can find some info about it?

[Poconos]

DO NOT dump DE in until you figure what you really have. A sand filter is nothing but a container almost full of filter sand. Incoming water is sprayed on the top and there is a mechanism to drain water from below the sand for the outlet. The valve assembly can be either top or side mounted but they do the same. Control the path of water flow between inlet from the pump, outlet to the pool, and waste. Have no idea what the other stuff is but something could have gunked up the top layer of sand. If you dig below the surface a couple inches see what you find. Should be just dirty sand. A DE filter is constructed totally differently. Please dig up any model numbers and any info that you can find to identify the equipment. Some info on the history of your pool would be useful too. You said it was one year old. Did you acquire it with a house? Install it yourself or have someone install it?
Al

[britinusa]

Could you post a picture of the filter?
Is there a label on the side?
I have a DE filter.

[Coach]

Sorry I have been out of town, but while gone one of my friends told me they were having the same problem and changed their filter sand. I did figure out that mine was a sand filter by the way. So this morning I pulled out the old sand, about the last 6 inches of it on the bottom was as hard as concrete, had to break it up to get it out. I guess this was the problem as it works like a champ now. I'm not sure what caused it to do this in just one season but I was vacuuming to my filter alot. Thanks for the help maybe this thread will help someone else too.