Backyard Aquaponics
A place to discuss aquaponics

Has anyone tried one of these sump pumps. I'm looking at if for my setup and am wondering if there is something I need to be looking out for.

I have a 275gal IBC fish tank which I have to change over at least every hour (I think). My head hieght is going to end up being 8.5' max assuming the sump went dry competely. So 4.6GPM at 8.5' head min.

I'm looking at this 1/8HP 5800-99 (curve A). It should supply about 12GPM at 8.5', which is about two and a half time what I would need and would cost $125. I haven't gotten a reply on what the power consumption is yet.

http://www.buyapump.com/pdf/97-98.pdf

Any input?

This is the setup we a constructing:

viewtopic.php?f=18&t=12940

Pump sizing is an interesting design issue with opposing requirements; you need to move sufficient quantities of water through the filtration in a reasonable time frame, but you don't want too much water moving too fast that it doesn't spend enough time in contact with the bacteria which do the nitrification work, or water moving so fast that it doesn't get filtered as it forced through the media.

As the bacteria are not 100% efficient and if they are not given enough time in contact with the water, they will not be able to process all of the ammonia and nitrites on a single exposure; you will still have trace amounts of ammonia and nitrites in the sump water even though it has already been through the filter. When you say that you want to move the FT water through the media once per hour, I'd suggest that you should be looking to move ALL of your water through the media, not just the FT volume which would suggest you need a large pump to fulfill this function, but then you'll end up forcing high volumes of water moving at high velocity through the media which is actually detrimental to filtering solids and nitrification. You might find the better solution is a smaller pump running for longer, if not continuously, or, if your pump volume exceeds your requirements, you could add a 'T' and loop some of the sump water back into the sump which aids aeration and doesn't add back pressure on the pump.


Scott

Each to their own , I dislike this option. This adds the worst of " Chop II " to a perfectly good set up. As Rupert and others have noted , you're just circulating poop in the fish tank. Poop to growbed good , poop in tank bad.
Size your pump appropriatly , keep airation seperate.
From experience I have turned off my bypass and won't go there again.

But the sump should be relatively clean water, so any access that is dumped from the sump back into the sump is added aeration. I'm planning on running CHIFT PIST and the pump is in the sump obviously in this case.

If Bunson is right and I want to move all my water twice an hour, then that would be the sump + the FT which are the same size at 275 gal. That would mean my pump is sized at 125% of my system which should be about right assuming some losses from pipes and some gain from when the sump is high.

I don't see it that way. If you have a pump that moves 200 gallons per hour and it all goes to the grow bed and you have a pump that pumps 400 gallons per hour but still send 200 to the grow bed there is no difference in filtration, but you are aerating more water with the bigger pump. With either set up you are filtering 200 gallons per hour.

+1

The pump is in the sump.

A pump that's twice as big as what you need it, is exactly that...

So that's about 2880L/h that's not too bad, definitely a little on the high side, like us using a 3000L/h pump in our IBC system..

Depending on a lot of factors including species, stock density and more, passing all of the water through the media once per hour can sometimes be considered overkill. I know some Koi-keepers who are absolutely pedantic about their water quality, but they only pass the water volume through their filters once every 6-12 hours. I certainly wouldn't be looking to go overboard and try to pass nearly 500 gallons through 4GBs twice per hour, once will be enough in most AP system designs. Look to have all of the water in contact with media for at least 10-15 minutes once per hour, and by that, I don't mean barrelling through the media from one end to the other blasting the solids and bacteria in raging torrents, the water should be moving sedately through the GB media. As previously mentioned, any "spare" volume is easily recirculated (ST to ST) providing additional aeration.

There is a conundrum with pumps and sumps; you might get to a stage where you say, because of the total system water volume the pump is required to operate continuously, but if this is the case, then what is the need for the sump? (Except to hold some "spare" water, and to have a ready established location to hold water if you decide to stop the pumping and drain down for maintenance or something, or your system is built on a slope.) Without the volume of water associated with the sump, you might be able to switch back to a timed flood and drain, but then you'd need a sump because of the fluctuations in water levels! (Unless of course, you just kept going with the small volume of water and continuous flow?)

This is why I advocate drawing good plans and iterating through the design over and over, before ever buying anything or lifting a shovel. It is much better that these factors become apparent at the start of the project than discovering something is awry after the system is installed and set-to-work.


Scott

Yep my bad

I guess it's a moot point now, they just told me they are discontinuing all pumps under 1/2HP.