Backyard Aquaponics
A place to discuss aquaponics

How effective is a Solids Lifting Overflow?
My problem is that I have an overflow plumbed into the side of my fish pond and every time I feed my fish some food goes into the overflow. I use a feeder ring but even that doesn't stop some food from going into the overflow.
I do wish I had gone with a bottom drain instead to remove solids from the bottom and keep all the food in the pond. Anyway, I saw a diagram for an SLO and was wondering if anyone with experience using them could tell me how effective they really are.
I see that they could trap fish on the bottom so I was wondering if anyone has run into that problem and how they overcame it (holes or slits in pipe or netting cover)? I am using 2" pvc piping if that makes a difference and I have had small tilapia get wedged into the plumbing before they all got too big to fit.
Also do SLO's really pull more solids through the overflow? I use a settling tank (vortex tank) after my overflow so getting more "heavy" solids from the bottom would be really helpful.
Mahalo for any help I receive.

depends on the flow rate. If flow is high enough, VERY effective.

Right now I'm using a pump that's supposed to put out 1000gph. I am pumping up about 5' so the flow rate is much less than that. I'm hoping to upgrade to 2000 gph soon.
Do you think I need to go higher than 2000 gph on a 2" pipe size?

Depends on how many GB you have, how big your FT is.
Is the 1000Gal/hr really too slow? or just a bit?
2" is nice for pipe size.

Right now I have only the pond no growbeds. If you mean fish tank by FT (sorry newb here) than the size is 1400 gallons.
As far as I can tell I like the flow. I just wanted to go higher to increase the turnover rate in my system and hopefully to get more oxygen into the system through my wet/dry.
My question is will the existing pump (rated 1000gph; probably more like 500-700gph w/ head) be good enough to pull solids through a 2" SLO? If not will stepping it up to a 2000 gph pump be enough or should I reduce the SLO intake size to 1-1.5".

Thanks for the responses KudaPucat.

Ideally you want to be able to pump the entire volume of your fish tank once per hour, so a 2000gph pump would be better.

1400Gal / hr @ required head.
You will find a graph or table in the pump's details that will tell you what height it can pump how much water. Buy you pump based on this. If you are not pumping very high, then a 2000 may be for you, if pumping higher you could need a 3000, check out the graph and buy what you need.

The Solids lifting overflows seem very effective at pulling solids out of my fish tanks so long as there are enough fish in the tank to keep the solids stirred up enough to get to the SLO. But that is because my tanks are mostly all rectangular and the inflow to the tanks does not necessarily push the solids to the outlet plumbing. Fish seem pretty effective at keeping the solids moving enough to get sucked out though. If no fish are left in the tank, what solids are there usually settle in the corners and stuff.

I use a grill or netting cover over all plumbing down in the tanks since it is amazing what a fish can manage to swim through.

Yep what TC said, as long as the solids are not getting trapped in corners or otherwise not able to make it near the pipe then an SLO will do quite well at removing the solids. I have had issues with fish getting trapped under the pipe and hurting themselves on the crenellations cut into it, or at least that was the most likely explanation. I changed the bottom of the pipe to have slits instead of notches and that helped.

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Thanks for all the responses. I switched my overflow to the SLO and immediately saw it suck a bunch of "stuff" right into the overflow. I have a square tank and the overflow is in a corner so that works out good for me. Again thanks everyone for convincing me and the SLO really is doing good. No more feed getting sucked into oblivion.

My SLO was going good for a while then one day I went to feed my fish and the fish tank water was siphoning into the top like an overflow. My sump was almost empty. I figured out that either the fish are getting stuck to the bottom of the SLO or there's not enough space between the bottom of the pipe and the liner (had about 1").
I re-read some suggestions and decided on cutting slits into the side of the SLO pipe near the bottom. Worked like a charm. No more empty sump. Thanks again to everyone's experiences. Priceless info as always.