My entire blue barrel system is plumbed from top to bottom with 3/4" pvc. I really didn't do any specific calculations but I did have the thought that I would rather have too much capacity than not enough if I decided to expand the system. I also am very big on using a standard size across a system when ever possible to make maintenance and repair easier.
you will get higher pressure in your supply lines using 3/4", which could shorten the life of your pump..
Wouldn't pressure be higher the smaller I go? So in other words, if I used a 1/2" pipe, the pressure would be higher than if I used the larger 3/4" pipe?
And also, wouldn't that pressure be relieved by having a T-connector to spray water back into the tank for aeration?
yes, pressure will go up with smaller pipe.. my first pump had came with 2 fittings, 1/2"x1/2" threadXbarb and 1/2"x3/4" thread by barb.. i used 3/4" tubing for supply lines, but changed to 1" pvc supply when i brought the system into the basement. i have much better flow with 1" pvc.. i did divert some flow back to the ft, but now i divert to a couple of bucket filters, i have valves to regulate the flow to the buckets, no valve on the growbed outlet..so i "set" the flow to the growbeds by increasing or decreasing the flow to the buckets.. i was talking about restricting the output of the pump in regards to it being harder on it..
if you have say 3 outlets from your supply, and none of them are "wide open" you will be restricting the pump
i was talking about restricting the output of the pump in regards to it being harder on it..
All pumps have a max head beyond which they can't pump. Any elevation whatsoever begins to restrict pump output. Whether that restriction is gravity induced from head height, or from output line size, or from valves makes no difference to the pump. It doesn't know the source of output restriction. Restricting INPUT to the pump from valves or clogged filters on the input side is bad because the fluid lubrication to the pump impeller is reduced and cavitation can occur when that happens, but restricting the pump output volume is not really going to hurt it.
also. don't go half inch like I did. I experienced cut off issues at one point and I have to use a t-connector at the bottom of my gb in order for it to cut off. also 3/4 will be better if you plan to expand. also the start with the 3/4 adapter to the end of my half inch stand pipe did not have any start issues with a 150 gph pump. so you should be fine as my system is 50 gallons.
yes, pressure will go up with smaller pipe.. my first pump had came with 2 fittings, 1/2"x1/2" threadXbarb and 1/2"x3/4" thread by barb.. i used 3/4" tubing for supply lines, but changed to 1" pvc supply when i brought the system into the basement. i have much better flow with 1" pvc.. i did divert some flow back to the ft, but now i divert to a couple of bucket filters, i have valves to regulate the flow to the buckets, no valve on the growbed outlet..so i "set" the flow to the growbeds by increasing or decreasing the flow to the buckets.. i was talking about restricting the output of the pump in regards to it being harder on it..
if you have say 3 outlets from your supply, and none of them are "wide open" you will be restricting the pump
I do plan to have 3 outlets with bell valves on each grow bed, in addition to a valve off the pump to aerate the tank a little bit. My plan would be to use this aeration line to take any remaining pressure off the pump which may be restricted by partially open grow bed valves, if that makes any sense.
In other words, I will start with the grow bed valves all the way OPEN, no restriction. I will then close them a little until I reach the desired flow output that I want. Let's say that I end up closing the valves by 50%. I would then open up the valve near the pump by at least 50% in order to take that pressure and return it back into the tank.
I just came back from buying a lot of my PVC supplies. I think the only thing I'm really missing now is my 2" bell cover and the 3" media guard.
I do have a question on glue though, and perhaps I should make this a separate topic. What PVC glue should I use? After all, I assume it has to be fish and plant safe. I bought something called "All Purpose Adhesive Sealant --- Aquarium Safe", but that is more for the seal around the opening of the grow bed holes I will cut (I think).
Here is a picture of it:
So is there a specific brand or source for what I should use to glue the rest of the PVC together? Would this stuff work for the entire system?
If you are going to glue up the joints permanently, you should use PC cement and PVC primer. I always just slip fit my joints until I get it just like I want it. It will leak a little but not to much.
My old man says when it's time to be counted, the important thing is to be man enough to stand up.”
? Robert A. Heinlein, Between Planets
I would use a 6" drain guard so you can get your hand down there and work if you want to modify something. I will be using this on all my future projects, the 3" is to damn small to get your hand in.
Also, if you can get an air pump and some air diffusers and put them in the fish tanks and if you can in the bottom of each grow bed. I always end up wanting to add this after I put in rocks. The place I am usually lacking is in dissolved Oxygen which is the name of the game.