Recirculation is OK but water cannot pump into filter

[atombob]

Hello all, I'm a new pool owner who just opened our pool a few days ago. The water is pretty dirty so the pool company poured lots of chemicals into the water and we kept pump running for a week.

2 days ago, after the pool company cleaned the DE filter (as the water is still green), the filter pressure went up over 30 in 2 hours after the backwash. We backwashed many times but still the same. Last night, the pump could not prime with valve turning to filter. Thought might be water lost quite a lot due to many backwash so we filled in fresh water and tried backwash. Pump was able to push air out and water flow is fine with valve turning to recirculate. But every time when we switch valve to filter, the pump won't prime. I don't think there is any water leaking.

I thought the problem right now might be the filter is blocked so may need another cleaning(and we don't have the tools to do it ourselves but pump company cannot come until late next week). Any suggestion or thought beside my guess?

Thanks so much!

 

[pooldv]

Welcome to TFP!

You've got algae growing in your pool which will quickly clog up a filter. It will need to be cleaned every day or two until the algae gets under control. Follow this process to kill the algae, SLAM Process.

You'll need a good test kit. I use the TF-100 and I buy mine from TFTestkits.net.

 

[RedBluePool]

Your Filter is clogged with algae preventing your pump to push water thru your filter grids and it needs to cleaned as he suggest^^^^ Just make sure you always add DE after backwashing.

But for now your best off running it on recirculate so you atleast have your water moving with chemicals to kill that algae.

 

[atombob]

Thank you both. Will try to clean the filter today and see what will happen.

 

[atombob]

We cleaned the filter yesterday. Yes, it is clogged with lots of DE around the water inlet at the bottom of the tank. We have a 30k to 35k pool and I just added about 3-4 lbs (the tank recommended 5-6). The filter only runs for 6 hours and pressure went up from 12-30. Does that mean it is clogged again? We backwashed twice since completely clean yesterday but the water is clear though.

I added PH to adjust around 7.2. CYA is around 30 and FC is around 4 now. I am going to shock it again in half an hour. Anything that I did wrong? If the filter pressure goes up easily again, do i need to do a deep clean again? Thanks very much!

 

[mknauss]

Read post #2. Shock will do nothing. You need to SLAM and you need a proper test kit to accomplish that.

This is not a filtering problem. This is a water chemistry problem.

Good luck!

 

[Richard320]

You can probably get by with just a backwash for now. That pressure jump is telling you that it's filtering out dead algae. What you need to do is get that FC up and keep it up so it will kill the algae faster than it can reproduce. That's when you'll start making headway. If you just diddle around with an occasional shock, you'll never get it all and you'll be fighting cloudy water and clogging the filter all summer long. SLAM Process

 

[atombob]

Thanks. Today the pool is not green but milky blue.

In the evening, I deep cleaned the filter again and did see lots of dead algae on the grid. Also I noticed a lot greenish calcium like residual at the top and bottom of the tank. I used ph up, stabilizer, shock and chlorine granules from different brands and they might have chemical reaction?

After I turned on filter, it runs ok for 1 hour without adding any DE. However right after I added about 3lbs DE (my pool is 35,000 so I didn't add enough), the filter clogged up again in half an hour. So I turned off filter and switched to recirculation.

Following the SLAM process, I brushed the side, added 2lbs of liquid stabilizer and 3 gallon of liquid chlorine. I plan to backwash and drain the filer tomorrow morning (or clean the filter again) and add another 3 gallon of liquid chlorine. Hope this can turn the milky blue to clear blue.