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RO/DI Setup


Calvinorc

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Just bought a Brute trash can to use for a RODI water storage tank, with an auto cutoff and spigot. Question I have is, what should I use (and should I period ) to wash it out prior to filling it?? Any soap NOT to use, residue issues, phosphate, etc?

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I used vinegar and RODI water to wash out my five gallon buckets. I've been using them for almost three months without issue. Soap probably wouldn't be the best idea because of the possibility of residue breaking down into phosphates like you mentioned.

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Ok, thanks. I was skimming posts a little bit ago and saw another reference to white vinegar removing any oil or residue from the Brute's manufacture... So you must be on the right track!! ;) I'll have to run to the store and grab some... Used up the last of what we had cleaning my coffee machine!!

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Ok, thanks. I was skimming posts a little bit ago and saw another reference to white vinegar removing any oil or residue from the Brute's manufacture... So you must be on the right track!! ;) I'll have to run to the store and grab some... Used up the last of what we had cleaning my coffee machine!!

 

I buy a gallon of vinegar almost every week now.

 

I use it washing clothes, cleaning around my apartment, and now to clean my aquarium stuff!

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Vinegar is the way tog for sure, its cheap to start off with, it works well diluted & you always know when you got rid of it cause your bucket doesn't smell of vinegar anymore. Also awesome for cleaning powerheads & pumps, i just run all of them in a bucket of water/vinegar for an hour. Come back and they are all clean without touching them, run them again in clean water and all is well!

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Use straight undiluted distilled white vinegar when possible. When you dilute it you raise the pH which cuts the strength so it takes longer to work.

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Not to hijack this thread, but I had a very similar question...kinda-sorta...

 

I have the Aquatic Life RO Buddie with the DI canister. The resin is needing to be replaced, and I have it on order but what's left is still doing a fairly decent job. So here are my TDS numbers:

 

Tap: 150

After RO membrane, before DI: 25

After DI: 3 (Was ZERO when the DI resin was new)

 

I collect my RO/DI water in a 20 gallon grey Brute trashcan. I rinsed it out with a very mild bleach solution before anything and then I filled it up and dosed it with PRIME and let it sit for about an hour, rinsed it out and it's been good ever since...

 

I had about 5 gallons left in the trashcan and decided to test the TDS as it's "bottom of the barrel" so to speak and I was shocked that it was around 110 TDS!!!

 

I run my RO buddie about once or twice a week as I've started using it for my 60g FW tank as well. So I decided to test the TDS of the water this morning RIGHT after connecting it up and turning it on, again, shocked that the water coming out of the RO buddie tested at about 900 TDS!! I let it run for a few mins and then tested again and the water was back down to 3 TDS coming out of the RO Buddie.

 

So my question is...does the water sitting in all the RO filters accumulate TDS as it sits there? possibly from sitting in the DI chamber and that's the cause for the first initial reading of 900 TDS from the water that FIRST exits the machine after sitting for a few days?

 

And a second question, this may account for the high TDS reading in the last of the water in my brute right? If there's an initial 2 cups (estimate) of water coming out of the RO Buddie at 900 TDS, then goes down to 3, that would get diluted and after a while cause the water to raise in TDS? Can water sitting in the Brute accumulate TDS by some other means? Bacteria?

 

Finally, do you guys let your RO/DI machine run for a few mins to flush out any of the water that sits in it before starting to collect it?

 

Sorry for the novel, but it fit in this thread without creating a new one!!!

 

Bryan

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What you are seeing is called "TDS Creep". It has been discussed hundreds of times on all the reef forums and is an easy search. Also DI resin starts to release weakly ionized substances even before it is exhausted and you are seeins this effect too. Replace your resin when you first start to see anything other than 0 TDS, not 2 or 3 as its too late by then. Use only fresh reef quality DI resin or cartrdiges too.

 

 

RO/DI is very agressive so will attract anything it can to get back to its natural "dirty" state. It wants to gain back those ions that have been stripped out of it by the membrane and the DI so attracts dust, salt residue leftover from previous water changes in the bucket or trashcan, things on your hands and arms, the residue from the powerhead you stick in it etc.

 

Always seal or place a tight lid on stored RO/DI water and don't aerate it until you are ready to use it, circulating the water draws contaminants like dust and stuff in the air raising the TDS.

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If you make your water manually it is very easy to install a DI bypass valve and flush the TDS creep down the drain. Install a 1/4" tee and ball valve between the RO membrane and the DI filter and open the valve to drain each time you start the system for a minute or so or until your handheld TDS meter shows normal RO only TDS which should be around 96-98% lower than the tap water TDS coming in then close the valve to make DI water. If you are automated its a little tougher but there are some automatic valves on the market.

Another thing you can do if you are using a simple float valve in a trash can is to shut the RO/DI off completely after filling the can and allow the level to drop to at least half or say 10-15 gallons stored before turning it back on and making new water. This gives you a nice long constant filter run so the membrane is well flushed and cleansed and TDS creep is minimized. When you make short spurts each time the level drops 1/4" the membrane just keeps building up TDS which eventually solidifies on the TFC fabric and it fails prematurely. Make at least 5 gallons at a time and try to use the system at least every 10-14 days so it stays fresh,

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good deal about the bypass between the RO and DI, I actually read another thread of yours this morning that mentioned it and it makes complete sense, off to Home Depot!

 

Yeah, nothing is automated so when I do make RO/DI water, I do at least 5 gallons at a time. Either refilling my storage can or making a fresh 4.5 gallons for new saltwater.

 

Regarding the TDS creep in the storage container, since DI water is so "aggressive" at gaining back the lost ions, is it better to not really store much water? I have the lid on at all times with only two 1/4" holes drilled into the lid, one for the line in and one to just let air escape when it fills. I have a 50g/Day RO/DI system so it's not like I can't make 20 gallons the night before fairly quickly.

 

Do you store much water?

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sorry to do it again....buuuuut do you have to add prime to rodi water?

Nope. What would be the goal of dosing Prime in 0 TDS water?

 

 

Regarding the TDS creep in the storage container, since DI water is so "aggressive" at gaining back the lost ions, is it better to not really store much water? I have the lid on at all times with only two 1/4" holes drilled into the lid, one for the line in and one to just let air escape when it fills. I have a 50g/Day RO/DI system so it's not like I can't make 20 gallons the night before fairly quickly.

 

Do you store much water?

 

The way I see it, the surface area-to-volume ratio would be more favorable in a larger storage container versus a small (or multiple small containers). Imagine you do have some contaminants in your RO/DI storage tank... if those molecules dissociate in 20 gallons of water rather than say 50 gallons, they would be more 'concentrated' (for lack of a better term).

 

Eg:

 

Surface Area (SA) of...

20 gal. Brute is (roughly 10 in. radius and 23 in. height) 2073 sq.in.

44 gal. Brute is (12 in. rad. and 31 in. height) 3242 sq.in.

 

Volume (V) of...

20 gal Brute is 7225 in^3

44 gal Brute is 14024 in^3

 

SA:V ratios

for a 20gal Brute is about 2:7

for a 44gal Brute is about 3:14

 

Bottom line is: the larger your storage vessel, the more diluted your TDS creep and leaching/airborne contaminants will be.

 

Personally, I try to run my RO/DI system 2-4 times a month. Prior to filling my storage tanks though... I valve off the DI cartridge(s), produce RO only until my TDS is back to normal parameters (2-3 ppm TDS in my case), then I fill up my drinking water containers :) RO water is delicious! I used to hike into the mtns to filter and pack out water I would deem 'delicious' lol.

 

Anyway, THEN I start filling up my RO/DI. Specifically, a 44 gallon Brute and 3 5-gal polyethylene carboys (just enough for a 2 50% WCs, for disastrous events. I like to make my filter runs (as AZDesertRat stated) as long as possible to eliminate TDS creep concerns.

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