Backyard Aquaponics
A place to discuss aquaponics

Thought I would just run over to HD to pick up some PVC for my drains...LOL.
I wanted 2 inch drains. 4-to-2 reducers. 5 inch bell pipes and domes. 6 inch media guards. Yeah, right.
Apparently, I am the only person in the world that didn't know you can'y buy 5 inch PVC. Or caps.
Sooooo...
If I have 1 1/2" SLO and PVC to the grow beds, can I use 1 1/2 inch for drains? That would allow a 4" bell and 6" media guard. I could control water to the grow beds with the ball valves. Plus of course, 1 1/2 inch fittings are considerably less expensive.
Any advice? I appreciate it.

It really all comes down to flow. When my system was much smaller I had Half barrel grow beds that was filled with 2" PVC and drianed via 3/4" stand pipe and 2" bell siphon. It all depends how much your pumping, size of grow bed etc...

More info is needed:

Pump size as in GPH
grow bedsize.

Is the 1 1/2" SLO feeding ALL the grow beds?

What size are the grow beds?

How fast is one grow bed being filled?

Thanks for the reply Lmannyr. Some of your questions I can't answer yet as I have just barely started construction.

viewtopic.php?f=18&t=27423

Pump size - around 600 GPH @ 6'
Fish tank - 275 gallon IBC
Grow beds - (2) cut down IBCs 175 gallons EACH, approx 87.5 gallons of water EACH.

I don't know how long it will take to fill one growbed yet, but I will have ball valves everywhere, so I can slow down the flow easily if needed.

Aside from my large system, I have a 1 IBC system. The typical half cut tote grow bed on top of the other half as a fish tank. It has a 3/4" stand pipe and 2" pipe siphon with a 4" media gaurd. Works perfect. Its powered by a small fountain pump around 400 gph ish. It's been so long since that pump is running I can't remember the pump size exactly. The pump is from home depot and fits in the palm of my hand. If you really need to know the exact size, next time I go to home depot I'll look at the fountain pumps and let you know. I'm at Home depot several time a week lately with my system upgrade. Anyhow, my pipe sizes have been great. That AP system has ALWAYS been growing LIKE CRAZY!! ALWAYS CUTTING IT back!!

It sounds like you're using gravity flow from the fish tank into the grow beds and that you have more than one grow bed. You should be OK with the drains and could even go smaller since the SLO probably won't be full as it drains the tank and since you're splitting the flow into more than one drain at the grow beds. Any excess flow can also be returned to the sump to aerate the water so there's a backup plan if you need it .

Cheers

Lmannyr. Thanks for the info. I have an Ace pump from one of my old gold separation tables, 575 gph @ 6 feet. 1/6 HP, 3/4" outlet.

Scotty, thanks for the advice. The pump will be in the sump tank, pumping to the fish tank, with a return back to the sump tank to keep the pump submerged at all times. SLO from fish tank to grow beds, siphons draining into sump. Ball valves throughout the system.

So - my new plan is 3/4" line from sump to fish tank, 1 1/2 inch SLO to the grow beds, and 1 1/2 inch drains, 4 inch bell and 6 inch media guards. I suppose I will still use 2 inch emergency overflows.

Any advice or comments before I go shopping again?

Those are some BIG drains... Go for it. If you have issues later, you can always slap on some reducers.

It's a good idea not to glue any of the pipes within the grow bed. This allows the cleaning of any distribution grids and also allows you to swap standpipes for changes in water level or a change to Constant Flood from a Siphon system with continuous flow as you're doing. You might want to shift to Constant Flood to prevent large water level fluctuations in your tanks or if you have troubles getting the siphons working the way you want. See the BYAP Trials thread for a comparison of three different system types - http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=8621

Actually you are not the only one who did not know about sewer pipe sizing and I've built my own house and the house my Ex now has, but that is another story. I wanted six inch thin wall PVC for our strawberry towers. I had the whole setup drawn out and in my hand at the local hardware store. I could not find any 6" fittings, and asked the store helpers, who had to ask the guys at the contractors desk, who flat out said, "Six inch drain & sewer PVC pipe, nope." I dropped my plans on the floor and got that stupid look on my face that sometimes gets a little help from the people at the store. In the end they were quite interested in my strawberry tower setup.

This is what we're using for media guards as well, 2" bells, 1" stand pipes.
Have fun, you are at a very fun stage of the setup, only it may not feel like it now.

Scotty - Yes, I had read a post or two about not gluing the pipes, but thanks for reminding me.

boss - LOL, yeah I know that feeling WELL. I am at one or another local hardware store several days a week, and I frequently have that look on my face.