I have a few 300 gallon systems that are a bit too overstocked with fish so they are always on the borderline of being out of balance. I have been looking to add additional beds but would like to do so without having to put in a sump.
It seems that indexing valves are a good way to do this and most of the information comes from TCLynx but she recommends not using indexing valves with auto syphons. As all of my media systems use auto syphons and I have not used any other technique, I was wondering if anyone can give me some helpful tips on alternate drainage methods, using indexing valves with syphons or other alternatives to add more beds to my system without using indexing valves.
With an indexing valve, a timer is used is used to sequence from bed to bed. Each time the timer starts the pump, the valve pumps to the next bed in the sequence. There is no need for a siphon and, in fact, it would be a very bad idea to use a siphon in this situation because the timer could stop the pump while water remains in the bed (before the siphon starts or starts again).
Standpipes are used in the grow beds when you use an indexing valve. A hole is drilled near the bottom of the standpipe and that is what drains the bed. When the bed floods, it floods to the level determined by the top of the standpipe (fills until it runs over, into the standpipe). So, at the end of the ON cycle, the water runs over the top of the standpipe but once the pump stops, the water slowly drains from the bed through the hole near the bottom of the standpipe. Actually, as soon as the bed begins to flood, it also begins to drain from the standpipe hole but the water is pumped in faster than it drains out, thereby filling the bed.
For multiple beds, you go with either the indexing valve or siphons with sump and I can't think of an alternative at the moment. My choice was indexing valve and I've never used a siphon.
Possibly you can add a grow bed or two without a sump. How many grow beds do you have now and what size?
George is right.
The use of a siphon with an indexing valve (which requires the pump to turn on and off to work) adds unnecessary complexity. Autosiphons are really only beneficial if you are planning on running your pump 24/7, which you can't do while using an indexing valve. Otherwise it's better to just drill a hole in the bottom of your standpipe.
Just remove the bell on your siphons and drill a small drain hole at the bottom of the stand pipe. That's about it.
Often bell siphons have that hole anyway in case of a power failure they will not hold standing water for hours on end so it won't even effect your siphons should you decide to go back to them later.
Jim's right. That should work. Careful to run your supply in such a way that media won't get sucked back into the supply line when the pump stops. That'll clog up the indexing valve.
Also, did you get the aquaponics version? The Home Depot version won't work.
Thats interesting. Why won't the home depot version work? was looking at different makes and thats the cheapest.
The manufacturer trims them special for aquaponics. The regular version needs more water pressure than a pump can supply. It's a special order so it's more expensive. It's nice to support Aleece too - she does a lot of good for people.