Backyard Aquaponics
A place to discuss aquaponics

IF you are going to use sand as a hydraulic sand filter like a swimming pool to remove solids then you are going to need a pump that can push some pressure. You will also need to plumb in valves to back purge it when it needs cleaning. Bead filters also work like that. My main concern is the colorization of anaerobic bacteria.

for some reason that got a good laugh outta me

Another point about pump head, the higher the head it has to pump the less flow

yeah I got the idea about pumps just a little hazy on the terminology. been a hydro gardner for years, usually just one plant though...

as for pressure in the sand filter, I think 400 litres of water trying to escape from an inch wide pipe would do it fine. have a look at my system diagram.

i recon not. You could have 4000L and it wouldnt make a difference, only the height of the tank, 9.8kpa per meter. most of the pool pumps work at a couple of BAR (100kpa to 200kpa) dont they?

I know the pool sand filter I have running has a pressure gauge on it (though the hands are rusted off so I can't read the pressure.) And The flow through it will fall off over the course of a couple days (with my currently clouded up water) and I need to backwash. I'm running a 1 1/2 HP pump with most of the feed currently going through the sand filter at the moment (as I've only two GBs right now and I have to restrict the flow into them to get the siphon to kick off properly.) Granted, this is a pool sand filter and definitely larger than really needed for this purpose but the pump and filter came free together so I hooked it up.

Anyway, if you are gonna have grow beds, why use a sand filter to stop solids, they are good for the grow beds.

Actually, using only gravity to take water from the fish tank, you might not get very much solids removal from the tank in the first place. Hum, maybe someone with a CLIFT PIS system using gravity to feed from the fish tank could share how their solids removal does?

I think I'll scrap the idea of a sand filter and see how I go.

Just design it so if you really want to try a sand filter, there is somewhere to put it later..

Boris 01 is using perlite in his flood and drain, and had to put a layer of gravel ofer it to stop it floating. I u wanna spend $$$ go for hydroton or just use gravel. Perlite is a bag full of headaches. I u insist on using it pit it in an old stocking or something to contain it.

I would not wish my perlite on my worst enemy

I called my fish supplier today to find out how much stock they have and fortunately they have heaps of everything. The only thing that has got my nerves pinched is what to species to put in my system. I wanted to grow redclaw but I don't know if the tank I have is really suitable for them. Every redclaw I've seen likes to hang around the bottom of the tank and I think it might be a little crowded. I'm going to go with either redclaw or sliver perch but I wanted to ask opinions before I decide. any thoughts?

and also... does anyone have an idea where I'd get a one way air valve from???

perch man, bullet proof, good starter fish.

One way air valve all good aquariam shops

is this what you are after AZ
http://www.aquariumproducts.com.au/cata ... rodID=2934

Agree with TT, SP are a good starter fish

that's it... check valve. I called up an aquarium today and they cost $9. that website you posted has them for 90c, WTF...

Anyway had a day off yesterday and got a bit more done. more pics by the weekend I hope.