Building a practical RO system

muleface

Well-Known Member
I have really hard water, it comes in at .6 EC. Its also really alkaline, it runs in the upper 9s. I would like to build a practical RO system. I am less concerned about the PH of the water. That usually drops like a stone when i add my nutrients to the water.

What i have started with is a 4x40 RO membrane and a 4x40 fiberglass housing. I am using a hose connected to my home water supply. It turns out i have picked up the wrong membrane for my situation, as the one i have requires a hell of a lot of pressure (225 psi to really work). They do make them for lower pressure systems like your home tap. Dow Filmtec XLE-4040 Extra Low Energy Commercial RO Membrane, I am sure there are other brands.

My thinking here is that for larger systems (i have a 110 gallon res tank) using an under sink unit is not practical. It wastes a ton of water and would take forever to fill my system. These 4x40 membranes can do 2400 gallons a day and i think are good for 20,000 gallons or more depending on your water quality. But with that said, you also need to ask, what is acceptable EC or PPM for your res water.

The current setup i have even with the wrong membrane drops my EC from .6 or 0, or 300 PPM to about 10 PPM. I suppose if after 20,000 gallons it went up to 30 PPM, does it really matter? My plants seemed to do ok with regular tap water. I am hoping they do better with RO water where i can better control what they are drinking.

I am also trying to figure out how much back pressure i am suppose to run here. I have a hose from my house running into 1 end, the other has a gate value on the waste out with a hose running to a drain. I am really only getting about a gallon every 5 mintues of RO water out of it.

I know im all over the place here, but anyone have any experience with these industrial RO setups?
 

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Observe & Report

Well-Known Member
Get another res or a couple of 55 gallon brutes plumbed together to hold your RO water then flick a switch on a pump to transfer it into the hydroponic res when you're ready to mix up a fresh batch. Long term a lot cheaper than a big RO and replacement filters and probably doesn't take up much more space.
 

JSB99

Well-Known Member
Get another res or a couple of 55 gallon brutes plumbed together to hold your RO water then flick a switch on a pump to transfer it into the hydroponic res when you're ready to mix up a fresh batch. Long term a lot cheaper than a big RO and replacement filters and probably doesn't take up much more space.
Or a rain barrel.
 
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