Sand Filter and 2 speed pump

[goonerbilt]

So I just upgraded my equipment to a 2 speed 1HP pump and went from a cartridge to a sand filter. The questions that I haven't been able to find on here yet are:

• Do I backwash and rinse on high speed only or is low speed beneficial in any way?
• When I switch from low speed to high speed should I set the filter on rinse for a few seconds first?
  • The reason for that question is that as my pool has started to clear up, I've noticed a 2 or 3 second burst of "stuff" coming out of my jet when I turn pump off of low speed, let it set for a few seconds, and then turn on high speed. (Haven't noticed it doing it when transitioning back to low speed though).

Thanks in advance

 

[goonerbilt]

So I did a quick rinse last night after I turned it off of low speed and turned on the high speed and did have what looked to be sand in the sight glass for about 2 to 3 seconds and it was all clear. I then moved it to filter again and all was good. Then before I went to bed last night I switched it back to Low following the same procedure, but no "dust" came out on rinse. So this is only a "thing" when going from Low to High.

As it is a brand new filter and fresh Ruby Sand that I have read has a good amount of dust in it, I am guessing I am still working on cleaning all that dust out. I back washed for about 10 minutes and then rinsed for 5 more when I first installed the sand to try to get most of the "dust" out of it, but I'm guessing I missed some.

 

[splashpad]

Is the sand filter big enough (aka rated) for the high speed setting of your pump? They have GPH/GPM ratings and your pump might actually be able to push sand out when first set to high speed. It could also just be new dusty filter media. How long has it been setup?

The other possibility, is it might be catching fine particulates from the water, so does need to do a rinse before switching to high speed. Is high speed needed for something? Because I would personally run on low speed, as it will improve the filtering as well.

 

[goonerbilt]

Flow rate at High Speed I can not confirm yet, as during install of all the new equiptment I found the flowVis I bought was build without an o-ring on the lid so I the nice manifold I built with the flow meter and ball valve is not installed yet. (Note: H2flow controls was very apologetic and send out an o-ring for me immediately and I should have it today).

I have a 24" (3.15 ft3 filtration area) filter with a max flow rate of 49gpm with a 1HP (fully rated) pump. I just installed all of this equipment last Saturday (6/6/20) so the filter media has only been in there for 3.5 days.

I only turn on the high speed in the evenings for a couple hours to vacuum (still opening pool) and to do a better job skimming what was missed during the day. Otherwise, I leave it on slow speed for better filtrating 22 hours a day.

 

[Bama Rambler]

I tried to look for a manual for that filter but can't seem to find one. Look in the manual you have and see if they list a minimum backwash flow. That will give you an idea if your pump is enough on low speed.

 

[goonerbilt]

There is no minimum backwash flow rate called out in the manual. Fairly useless manual as well if I might add. Luckily I'm a Mechanical Engineer and read a lot in here so I didn't need too much support from the manual to make sure I got it all set up and going good. If my O-ring for the FlowVis is there when I get home (as it should be), Ill get it installed and test my flow rates on the backwash side during a backwash just to see what it is there and then I'll install it into its permanent side on the filter side for those readings. Figured it would be nice to have high/low values on both sides.

One note on that crappy side for this filter . . . It came with a pressure gauge, but the only place there was to install it is where the air bleeder is at. The port for them is a 1/4" NPS female thread with the bleeder sealing with on O-ring. It took about 7 wraps of teflon to seal the NPT threads on the gauge. I'll be machining a custom tee in the next couple days to be able to install so that I can put the back mounted pressure gauge in the top of it (so I can see it by looking down from deck) and then have the NPS threads on the other side to put the vent plug in so I can still have both features.

 

[doug wilcox]

if it is a brand new filter with brand new sand
you need to set the multiport to rinse before filtering. this will
get rid of the fine sand i think you are desciribing

 

[goonerbilt]

Thank you Doug, that is what I'm doing right now. I'll continue doing it. The O-ring didn't show up yesterday, so looks like I've got another day to wait to see the flow rates.