Big new RO storage tank... wrestling with over fill control methods...

I've got this 100 gallon tank coming... as a replacement for my current 35 gallon drum...
And I've been thinking about overflow methods...

the tank is translucent, so I can easily see the water level... but I have overflowed slightly, a few times, my current smaller tank, in reality with my use, & the bigger tank, I will probably never accidently overflow the new, bigger one... but long term, maybe if I'm gone for a week out of town, ( which I never really do ) I initially thought about putting a float valve on the tank... but mechanical things have a way of not working when you need them to... ( I have a float valve on my Boiler feed water tank at work, they are replacing right now, so even commercial ones any more don't last... so lately I've been thinking about having the tank fully sealed, & put a port in the top of the tank, or better yet, in the big center cover, so I don't have to drill any holes in the tank, & run an 1/4 inch line, as an over flow, to the same drain the RO waste water goes to... as slowly as it fills,,, it would waste some RO water, but only when the tank overflows, which should be like never really...

thoughts???

I installed an overflow near the top, I used a wine bottling spigot and tubing bought at the same place. Directed the tube in the drain. It's big enough not to be overrun by my small RO/Di unit.



I measured how much time it takes to fill the tank and programmed an alarm on my phone. So if one day the pressure is a little higher I wont come back to a disaster.

I have 300 litre and 25 litre RO storage tanks. I have never overflowed the large one as it is so slow to fill and is in my living space so I get so much warning that it is getting full.
The 25 litre buckets are another matter and I regularly have had small floods. I now tend to put an alarm on my phone to remind me to check and turn off the water. I now know pretty much how long it will take. The system seems to be working for me so far !

This is the big center cap on this tank, in the middle was a 1 way air valve, to prevent a vacuum when draining the tank… I’ve removed that valve, and threaded it in 3/4 NPT threads, where I’ll screw in a stainless nipple, and a “T”, with correct size push lock fittings for my RO water inlet in one side, and a 1/4 in drain line in the other… the drain line will run up to the ceiling joists, so if the tank fills, it won’t syphon out.. there was a boss there for the syphon valve, so my choice of thread size was determined by that size…this cap will almost never need to be removed, but the push lock fittings will allow me to remove them easily from the cap, should I need to unscrew it…

Cap is ready for the push lock fittings for the RO water inlet, & the over flow drain lines... no brass, or black iron fittings, everything will be stainless or plastic...

next thing will be to fabricate a manifold, & lines, to divert RO water from the pump, to the 3 areas of the house that will have tanks needing RO... I fortunately bought a Diaphragm pump that stalls, as its for pressurizing plumbing systems... so I can just put a shut off valve at the end of any of the feedlines to the other areas of the house... I currently use 1/2 inch silicone hose... once I'm at the point of adding the manifold, probably all lines will be 3/8" hard plastic lines, with shut off valves at the ends... my 1/2 inch hose I don't use a shut off valve, as the RO & Storage are in a work area behind my main group of tanks... once I'm setting up the 250 gallon tank in the living room, I'll have to run that line... there is no water or drains close to where that tank is going... so I may have to add a service drain, for water changes, that will just drain out to the lawn, & run this RO line there, just for that specific tank, as it'll be a soft water tank

I use a float-valve which is what i think most people use. I use a well pump to move the water from the storage tank to other parts of the house. The well pump is pressure driven - open the valve - pressure drops and the pump comes on to maintain the pressure level; close the value the pressure increase and the pump turns off.

That’s the same way the diaphragm pumps operate

Next step….

Building the manifold to pump RO water to tanks around the house… the pressure stalling diaphragm pump, will go into this manifold… waiting on 2-1/2 inch threaded “T’s”… then will have 3 different RO feed lines…