Hi RIU. Just completed a DIY water reservoir build yesterday, figured I’d share the idea with others incase they’re interested in building something similar. I’ll provide links to the parts I used below. The harsh reality of growing is that lugging heavy jugs of water around can be quite laborious. I use a R/O water filter on the utility sink of my house, so I devised a plan to hook up a holding reservoir to the clean water line of said RO filter. I’m transitioning to a flood & drain style of growing, which is going to require me to have a larger supply of clean water on hand for reservoir changes. Here’s what I came up with… Parts needed: Plastic container used as the reservoir – I used a 32 gallon recycling bin from Home Depot. https://www.homedepot.com/p/Otto-Environmental-Systems-32-Gal-Blue-Recycling-Container-with-Lid-1332BLU/205199008 A ¼ inch float valve. I sourced mine from a local hydro store, but if you do enough searching you can find them online. Amazon has a few models. For the one I purchased I needed to drill a 7/16’’ hole… Since I don’t have a 7/16 bit I just used a 3/8’’ bit and used a utility blade to widen up the hole to make it work, it was very easy. https://www.amazon.com/HydroLogic-728912-Hydro-Logic-HLFV4-Float/dp/B0030065YW An aquarium air pump with air stone. I had an old air pump laying around unused which fit the bill perfectly. Optional Parts: I added a spigot to my reservoir, but looking back I probably didn’t need to, actually I know I didn’t need to. The extra 130 gallon water pump I have laying around can do everything the spigot does. Nonetheless I installed one about 11’’ from the bottom of the reservoir. I used a 1 ¼ hole saw to cut the hole, and a heavy amount of pipe tape on the treading. No leaks, viola! (don’t attempt without using plumbing tape) https://www.amazon.com/RAINPAL-Barrel-Quarter-Bulkhead-Fitting/dp/B00NX697C0/ref=sr_1_3?s=lawn-garden&ie=UTF8&qid=1517855655&sr=1-3&keywords=bulkhead+spigot ¼ x ¼ quick connect ball valve. I purchased mine from Home Depot but here’s a similar item on Amazon. I look at ball valves as a low cost investment to keeping things from going haywire, like water leaking everywhere by accident. https://www.amazon.com/Valve-Quick-Connect-Mountain-Products/dp/B01HVJIKZE/ref=sr_1_1?s=lawn-garden&ie=UTF8&qid=1517856862&sr=8-1&keywords=1%2F4%27%27+od+connector+water ¼ x ¼ quick connect tee. Again, I purchased mine from Home Depot but Amazon does stock them. You’ll need this if you want to split the water line so you can still use the faucet attachment of your RO system. https://www.homedepot.com/p/1-4-in-x-1-4-in-x-1-4-in-Plastic-Tee-PL-3003/100188178 The Tee & Ball Valve are optional but for $20 are worth their weight in gold. The Tee is used to split the water line coming out of the RO filter so I don’t have to disconnect the water line and reconnect it every time I use the faucet, i.e. filling drinking water jugs. When the reservoir is empty or filling up, the faucet won’t work (because no water pressure since float valve is open) which is why I added the ball valve and hooked it up to the water line that’s connected to the storage reservoir (ball valve is placed after the Tee and before the Float Valve). A quick flip of this ball valve and now the water pressure goes back to the tank/faucet like before this project. One quick flip back and the reservoir is being filled up again. When the reservoir is full and the float valve is closed shut, the RO tank will fill back up and create water pressure for the faucet to work like normal. FYI - Before I filled the reservoir with water I put a 4-wheel furniture dolly underneath it – making it really simple to wheel around the growroom when it comes to filling up other reservoirs. I just throw my small 130 gallon water pump inside with ½ tubing and filling reservoirs is now a breeze. Total cost was around $65-$70. Had I not included the bulkhead spigot I could’ve done this build for around $50 out the door. I just wanted to do this quick write up and share the information in case anyone stumbles across it and finds this helpful.