Do I have a problem?

SteveK52 · Jul 17, 2019

Yesterday I did a backwash on my STA-RITE DE filter. 3 Backwashes for 2 minutes each at approx 50 gpm and then a 10 sec rinse. I then placed a slurry mix of DE (75% of original DE capacity, 2.8 lbs (might have put a little more, between .1 and .2 lbs)). After about an hour I shut the pump off cleaned the strainer and lube the "O" ring, started the pump back up which took a little bit to achieve its prime. Bled air from the filter. Shortly afterwards I noticed the pool water was not as clear as it had been before the backwash. I assumed some how some DE got into the pool. This morning I ran the robot cleaner and the filters had DE in them. Any suggestions?
Steve

Jimrahbe · Jul 17, 2019

Steve,

I almost always get a little DE in my pools, after I recharge the DE filters.. For me anyway, the key is... does it continue. If not, I don't worry about it.

I have quit backwashing my filters.. With a VS pump running at a low RPM, I can run them for six months between cleanings.

When was the last time you opened your filter and cleaned it? The first time you backwash, you only get about 80% of the dirty DE out. The next time you only get 80% of the 80%, etc... You can't backwash forever.

Oh, and the answer to your question is... Yes...

Thanks,

Jim R.

SteveK52 · Jul 17, 2019

Jim,
This is a new installation this year and this is only the second time I have backwashed. I am running very low pressure through the filter (less than 5 psi). I guess I can go for a longer period maybe six months. I will continue and if the robot doesn't stop showing signs of DE I will need to dig deeper. Thanks for taking the time to respond.
Steve

Jimrahbe · Jul 17, 2019

Steve,

The official TFP way to know when to clean, or backwash, your filter is when the the filter pressure has increased more than 25% over the clean pressure.

I personally do not believe this works well for VS users... While not a TFP recommendation, I personally only worry about the actual return flow going back to the pool.. For me anyway, I can't feel any decrease in the amount of flow coming back to the pool, even after 6 months... I only clean them after 6 months, because my OCD will not let me go any longer. For the cartridge filter I have at my house, I'm sure I could go a year between cleanings if I wanted.

I do use hairnets in my skimmers..

Thanks,

Jim R.

SteveK52 · Jul 17, 2019

Jim,
Thanks, I am also using the hair nets which keep a ton of stuff from getting to the filter. I am going to follow your recomendation of every six months.
Steve

SteveK52 · Jul 17, 2019

Jim,
Something I neglected to mention. Before backwash my wattage was 150 watts and after it is 100. Seems like it might be significant enough to do the more frequent backwash.
Steve

Jimrahbe · Jul 17, 2019

Steve,

I only have a VS pump, not a VSF pump.. but if I did, I would not run in the "flow" mode... For years we (TFP) only recommend VS pumps and not VF pumps... Then Pentair came out with a combination VS and VF and everyone started using the VF thinking it was better. Not sure why? :scratch:

That said, it is your pool and you should do whatever works best for you.. That is what I do..

Backwashing more will not hurt a thing, it is just more work.

Thanks,

Jim R.

SteveK52 · Jul 17, 2019

Jim,
I'm not sure what the difference is, I can look at Sreenlogic and it will tell me what the RPM is that is associated with the GPM and I can see that might vary a little with temperature. What would be different if I set the RPM vs the GPM?
Steve

Jimrahbe · Jul 17, 2019

When you run in the RPM mode the RPMs are fixed and the flow increases or decreases depending on the resistance to the water flow.

When you are in the GPM mode, the flow is fixed and the RPMs change to maintain the flow..

It is not a major deal, now that there is just one pump, but often new people get fixated on a specific flow rate like 35 GPM. An example might be that they read a SWCG takes x GPM so they set there pump to that number. When in reality, the SWCG may work just fine at half that number, so you are just running faster than you need.

One of the things that we use as a tool to determine if a filter is working, is to ask about the flow out of the returns.. When that flow is low, it is almost always because of a dirty filter. When in the GPM mode, the flow will just keep increasing as the filter gets dirty, so in a way it masks a dirty filter.

Maybe we can get one of our pump experts to chime on on the subject.

Thanks,

Jim R.