First time backwashing, did I do it right?

[thecabana]

Hello! I'm a new pool owner of a previously built in ground pool, ~17000 gallons. For the first 2 months we lived in the home, I hired a pool company to help take care of the chemicals and equipment so we could settle in. They cleaned our Hayward DE filter at the end of May/early June. They have no record of backwashing since then, so I don't think they did. So I backwashed today.

I have a variable speed pump. This morning when I looked at the pressure before backwashing, it was
10 psi at 1500 rpm
25 psi at 2755 rpm
32 psi at 3200 rpm
35 psi at 3450 rpm

I was advised to measure the pressure at 3000rpm+ and also backwash on that speed.

So I backwashed and rinsed a few times until the water cleared up. Recharged with DE. Unfortunately I lost more water than anticipated so had to add water, help the pump prime, bleed some air from the filter. That all seems to have worked okay and pump and filter seem to be working well. DE seems to have recharged okay. With all of that, the pressure at 3200rpm went down from 32psi to 26psi. Did I not backwash enough, or is 26psi an ok clean pressure? I'm so afraid of messing up the equipment

 

[1poolman1]

Hello! I'm a new pool owner of a previously built in ground pool, ~17000 gallons. For the first 2 months we lived in the home, I hired a pool company to help take care of the chemicals and equipment so we could settle in. They cleaned our Hayward DE filter at the end of May/early June. They have no record of backwashing since then, so I don't think they did. So I backwashed today.

I have a variable speed pump. This morning when I looked at the pressure before backwashing, it was
10 psi at 1500 rpm
25 psi at 2755 rpm
32 psi at 3200 rpm
35 psi at 3450 rpm

I was advised to measure the pressure at 3000rpm+ and also backwash on that speed.

So I backwashed and rinsed a few times until the water cleared up. Recharged with DE. Unfortunately I lost more water than anticipated so had to add water, help the pump prime, bleed some air from the filter. That all seems to have worked okay and pump and filter seem to be working well. DE seems to have recharged okay. With all of that, the pressure at 3200rpm went down from 32psi to 26psi. Did I not backwash enough, or is 26psi an ok clean pressure? I'm so afraid of messing up the equipment

The best way to know if your numbers are good is to completely teardown and clean the filter, add the required amount of DE, and record starting pressure at a speed you will use as the benchmark. A 6psi drop after a backwash might be a good number for your system. Every pool is different.
It is good to remember to only add about 80% of the DE capacity to a filter that has been backwashed and not torn down. Backwashing never removes all the old DE.

 

[thecabana]

The best way to know if your numbers are good is to completely teardown and clean the filter, add the required amount of DE, and record starting pressure at a speed you will use as the benchmark. A 6psi drop after a backwash might be a good number for your system. Every pool is different.
It is good to remember to only add about 80% of the DE capacity to a filter that has been backwashed and not torn down. Backwashing never removes all the old DE.

Okay thank you that's good to know and very helpful! So the main speed I'll use is where I'll want to measure/benchmark it, not the highest speed? It runs at 1500rpm for about 6 hours and 2755 for about 6 hours on a schedule.

Yes - I think to completely start over my filter needs 7.5 scoops of DE and I put 5 scoops in after backwashing, does that sound about right?

 

[PoolStored]

record starting pressure at a speed you will use as the benchmark.

So the main speed I'll use is where I'll want to measure/benchmark it, not the highest speed? It runs at 1500rpm for about 6 hours and 2755 for about 6 hours on a schedule.

Just choose a speed and use THAT speed for your baseline pressure and to check you current pressure. Needs to be the same speed for both measurement. Doesn't have to be run speed, but it can be. Just don't use a low RPM, it won't show a pressure rise.

I have a pentair Superflo VS. My top speed is 3450. I happen to choose 3000 to check my baseline and current pump pressure. I run my pump 24/7 at 1400. After I backwash, I run the pump to 3000 and note my pressure. Every week or so, I run my pump up to 3000. If my pressure has risen 25% over my baseline pressure, I backwash. At 1400, It doesn't move from 6.5psi, at 3000 it shows the resistance of the dirt in the filter.

You could choose 2755 for your "filter pressure check" speed, would make it easier to check, never have to fiddle with the pump.

Hope that makes sense!

 

[PoolStored]

Oh, and WELCOME TO TFP!!!!

 

[Lake Placid]

Yes - I think to completely start over my filter needs 7.5 scoops of DE and I put 5 scoops in after backwashing, does that sound about right?

Hayward filters require 1 pound of DE per 8 square ft. of effective filtration rate for clean pre-coat. After a backwash use 80% of that number. 5 - 6 scoops sounds about right if 7.5 is your clean pre-coat amount.

 

[thecabana]

Just choose a speed and use THAT speed for your baseline pressure and to check you current pressure. Needs to be the same speed for both measurement. Doesn't have to be run speed, but it can be. Just don't use a low RPM, it won't show a pressure rise.

I have a pentair Superflo VS. My top speed is 3450. I happen to choose 3000 to check my baseline and current pump pressure. I run my pump 24/7 at 1400. After I backwash, I run the pump to 3000 and note my pressure. Every week or so, I run my pump up to 3000. If my pressure has risen 25% over my baseline pressure, I backwash. At 1400, It doesn't move from 6.5psi, at 3000 it shows the resistance of the dirt in the filter.

You could choose 2755 for your "filter pressure check" speed, would make it easier to check, never have to fiddle with the pump.

Hope that makes sense!

This is very helpful!

This may be a silly question, but what speed do you run your pump for backwash & rinse?

And thank you for the welcome! I already am really appreciating all the resources on TFP!

 

[thecabana]

Hayward filters require 1 pound of DE per 8 square ft. of effective filtration rate for clean pre-coat. After a backwash use 80% of that number. 5 - 6 scoops sounds about right if 7.5 is your clean pre-coat amount.

Thank you! That makes sense - I have a DE 6020 60sq ft filter.

 

[Lake Placid]

Thank you! That makes sense - I have a DE 6020 60sq ft filter.

Here’s a manual for your filter if it helps, the 6020 uses 7.5 pounds of DE as clean pre coat amount. https://hayward-pool-assets.com/assets/documents/pools/pdf/manuals/Manual362.pdf

 

[PoolStored]

This is very helpful!

This may be a silly question, but what speed do you run your pump for backwash & rinse?

And thank you for the welcome! I already am really appreciating all the resources on TFP!

Full Speed