afewpotsapot

I recently purchased an RO unit for less than 50$ (bargain!) and it seems to be working great. PPM before is nearly 500 and after is under 20 (guess it's had a bit of use.)

Does anyone know how long you can keep RO water for before it goes off or becomes contaminated?
Also if I just use the RO unit weekly, will I need to remove the membrane and stick it in the fridge with a bit of water or will it remain moist inside the unit for the week?

Cheers

Quantrill

The length of storage for the water depends on the container. Light and air tight container should be able to store the water for a year or more.

I dunno about the membrane storage. I would think it would stay wet inside for a week especially if you were careful not to dump what is in it out as you move it. but I have never tried it.

toke it easy

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Magical Cabinet

Your RO unit doesn't sit under the sink always hooked up? I'm not sure what you're working with, but I would just leave the unit full of water and cap the lines if you put it away after each use.

Storing the water is no problem, I usuall fill up those 5gal water cooler style jugs w/caps. I can see no reason it would go "off" as long as it's sealed up...not like your drinking it. Which is actually why I mentioned the sink. I have mine plumbed into a mini storage tank w/separate spigot, so we can drink it too. It's not just good for the plants dontcha know.

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Cannabis

afewpotsapot there's another little factoid i think you'll be really glad to hear, once you learn I didn't get to, and whacked the membrane on my excellent used one: the carbon filters that precede your RO membrane, MUST be kept in functioning condition, i.e. not allowed to have the carbon's absorption limits passed, or they'll pass chlorine, & it'll destroy the membrane and it won't filter water well any more.
LoL i bought a used one and it worked GREAT; I had it running for about a month and a half, and it started passing higher & higher ppm water... couldnt figure out... what tha... heck... connections, etc, all still good... got on the 'net: read about them some, and reasons for slow rise in ppm. Lo & behold, sure enough: went down, took lid off 'cleaned water' and put my nose to it in there, very very faint whiff of chlorine.
Carbon filters had exhausted. Had to buy new carbon filters - mine has two - and new membrane. Little 'Ouchie' to the tune of an extra 35 bucks off Ebay, plus shipping, on that one.

If I had the opportunity- I'd say to you, go to the store fairly soon; and buy new carbon filters so you have a known-good expiration date to reference to, and spare yourself the experience of finding out the ppm is slowly rising, and... yea, those carbon filters had expired 'cause you didn't know, when they were bought & installed previously.

afewpotsapot

Thanks for the feedback guys that's some good info. I will be buying a set of replacement filters when I got a bit more cash to spare but for now it will have to do. As for keeping it hooked up permanently... I was going to get an adapter for the outside tap, but in removeing the hose I managed to bust the tap and now it's leaking pretty seriously!
Now here's the problem... I've looked for the stop tap so I can replace the garden tap and the only one I can find on the ground floor is guess where.... in the grow room/closet! And it don't work!!! Scared to call a plumber out as I know they're gonna ask to look in it! Looks like I've got a permanently leaking garden tap on my hands, and it's pissing it out with 3 1/2 weeks till harvest!

HydroSan

Membranes last longer is the filter is pressured up all the time, i.e. the off tap is after the filter system. If water pressure is only applied during use, the membrane stretches with all that pressure on, pressure off malarkey and won't last as long

Stored RO water life will depend on the clenliness of the container, temp, and light stop properties. Bacterial blooms are common in RO water (clear jelly like substance) it can happen in the res too. Nutrient companies recomend mixing RO water with tap water to help buffering, and also help prevent the bacteria population exploding, I mix mine to an initial EC of 0.3 which is much more stable in the pH dept, and provides some Ca & Mg

San

Oh So Grow So

do know off the top of your head what the ratio is to get that? 60/40 R/O / Tap?

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FalconJerk

Ditto. I also “T” off a line to the ice maker in my fridge. That way when my ice melts it taste like water, not @#%! It also keeps the RO in use every time I use ice.

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HydroSan

It's going to be different depending on the initial EC of your water, and efficiency of the RO filter.

My filter produces 0 EC, or below 0.1 EC as thats the lowest measurement on my meter. My tap water fluctuates between 0.6 - 0.9, so the mix is probably just over 1/3 tap. I just fill the res with 2/3 RO first, then top up with tap water until i get 0.3 EC FWIW Canna recomend an initial EC of 0.4, but my tap water is especially shyte (high sodium & potassium), so I mix less and never let the res get below 1/3 full to aviod accumilation issues. I'm experimenting with just topping with RO/nutes to extend the life of the res, I've not had any issues up to 3 weeks, but I didn't want to push it any further, so I change out at 3 weeks on that mix. My res has about 20L per plant.

San