Mixing RO / Tap / Muriatic Acid

[roger]

Hello All,

I just got my RO unit in yesterday and Ill have it up and running tonight.

I got this since Im picking up some wild discus which are being kept in water that has a lower pH and gH/Kh than what I have.

From my discussions with Walter at airwaterice.com I expect that the RO will take care of gH/kH and also lower the pH (some probably to about 7.4). Out of the tap my water is gH 14 kH 4 and pH 8.4 and it stays pretty stable when airated.

I have been playing around with muriatic acid with my tap water and Ive gotten a feel for bringing the pH down to about 7. Since my goal is a pH of about 6 to 6.5 I was wondering what people thought about the best way to mix everything. Acid to RO then mix with tap?

RO and tap first....get your water stable at the conductivity you'd like to keep it at....then add the muriatic acid...monitor it very carefully on a regular basis, just incase it head's south...

Roger, To further bring down the gh and kh as well as ph, you might consider placing a deionizer behind the R/O. This will bring down th TDS--therefore lowering all the above. Deionization also completes the job of removing silicates. Together it is a match made in heaven!

Try not using chemicals to alter what can be done with more equipment at a little additional expense. The anion and cation resins when placed behind the R/O unit should last up to 2000 gallons before expiring. if you have a two stage mixed resin cartridge--you move the furtestmost gartridge to the front and replace it with a fresh one. Adding acid will increase your conductivuty--therefore increasing gh and kh.

I hope this makes sense! Joe :D

[roger]

I almost went with a DI bed in the RO system, but I think they are planning on switching over to chloramines where I live. The chloramines just tear up the DI bed in nothing flat.

If I can get my gH down to about 4-5 and kH to 2 I would be willing to live with that. Guess its experiment time tonight along with painting tank time.

I need to prep a couple of tanks for qt and one as a breeder tank.
So its a busy night playing in the water :)

[Carol_Roberts]

Adding muriatic acid will raise your total disovled solids and increase conductivity, but should not change hardness of water.

It will be interesting to see how long your membrane lasts with water as hard as yours . . . . liquid rock is right, lol

Carol :heart1:

[Steve_Warner]

Hi all,
Roger, Carol is correct in that Muriatic Acid(37%Hydrogen Chloride) will RAISE Conductance and total dissolved solids, but will not add hardness(usually expressed in terms of Calcium Carbonate equivalent). It is the same concept as using Salt(Sodium Chloride) to "Soften" your home water supply of "Hardness". It is used to drop pH due to the Hydrogen(Hydronium) ions it releases into the water body. It is an inorganic acid, which is extremely unstable to use, so do you know what you're doing with it? Please don't take this question the wrong way, I'm not meaning to sound like an a$$, but it is really dangerous to fiddle around with acids, especially in water with almost NO buffering ability. How about using peat to naturally lower it, or letting nature do it's job by slowly dropping the pH with acids via Nitrification? Just some thoughts

Steve

[roger]

Hey Steve

Your points arent lost on me at all. The stuff is extremely nasty, I played around with a 5 gal bucket and with and an airhose for a week before I felt reasonably sure of trying it on my water aging tank. tap is 8.4 pH gH 14 kH 4-6 and its stable even once in the tanks

I have pretty hard water both gH and kH so the pH bounces pretty good when I add this stuff. I run the aging tank for 24 hours with an AC and airstone, yes I know I could use a power head (will be switching to powerhead this weekend I have one that Im not using and I need th AC for my new tank), but I was using the AC for putting peat in. Anyways I check the pH in that tank before I do water changes and if its not 6.5-7 then I siphon out water and replace it with tap and run it for another 8 hours. Ive gotten better at the game, I usually dont have to do any fiddling after the 1st 8hrs, so by the time 24 hrs is up everything is stable.

Of course Im adding RO to the mix now so Im relearning all of this again. The RO is for wild discus .. Got the RO unit last night :)

The RO will help reduce the amount of acid that I need since there is no buffer in RO. I'm thinking that Ill be dosing the RO water to bring the pH way down then adding tap to bring the pH and gH back up. Im shooting at getting gH to 4-6 and kH down around 2.

All that and I almost didnt answer the complete question. I am getting wild discus in and Im trying to lower the pH down to the 6-7 range. I havent found a way to run peat yet on my aging tank to get the results I need, the water is just to hard. I do 1/4-1/3 wc on my tanks atleast every other day. The water changes just keep the pH stable. BTW my tank raised discus love the water, they keep laying eggs and I think they even had wrigglers the last time around.

Peace,
Roger

[Dennis_Hardenburge]

Roger
The PH will drop with 100% RO water with ageing, in your situation I would probably use 100% RO water and reconstitue it with RO Right or another product to get the conductivity you want. The ph will go down because th ro has removed the buffering capacity of the water, you might need to age the water a little longer than over night.
I would certainly play with it a bit, the acid is a pain in the butt.
Dennis

[roger]

I just got my RO unit working last night and it is something to behold. Pure clean water ..

I really need to find a 2nd or a larger water storage system. Im currently using a 55 gallon aquarium and water sits generally for about 24 hours before I use it.

Sometime next week Im going to take the time and fill a bucket with RO water and put an airstone in. Just to see what the pH ends up being at.
I should be able to get some sort of idea from there which way to go. In theory I think I calculated 2.5 gallons of RO to 1 gallon of tap will bring me down to gH that I want. The only thing Im not sure of is what the pH will be at that ratio. I might be able to run the 1 gallon of tap through a peat bed to bring the pH down before the mix.

Its going to be a fun few weeks.

[Dennis_Hardenburge]

Roger
I think peat is great stuff and the fish really like it, but it is a nuisance to mess with.
So I just use a larger percent RO water to get my ph where I want it then add RO Right to get the conductivity where I want it.
The longer RO water sits the more the PH will fall because it has no buffers, so how long you age might be what ph you are trying to achieve.
Of course this is just for breeders and all others are in tap water.
Dennis

Roger, I also have chloramine. The mixed resin Di cartridges after the R/O last around 2000 gallons as I said. The chloramine will be all but gone after the prefilters and membrane on the r/o . Joe

Hi all,

Joe I have made the same expierience with my DI cartridge.
I was done after 200 gal. After replacing both RO and DI membrane I got the same result again. The unit also has 1 Particel (sp) and 2 Carbon filter befor the membran.
I am not sure but are you talking about a different DI setup
(mixbed) ?
Thanks for the info

Ronald

Ronald, Yes , my DI is non-color changing medical grade anion and cation resin cartridges. The prefilters are a three stage process. Entering, there is a sediment filter followed by a high silicate removal cartidge followed by a carbon block. The two 100 gallon per day membranes are then followed by the two stage DI. The TDS after the mebranes is 12. After the DI, it is 0. I then regenerate the R/O water with 3 grams Calcium Sulfate, 1 gram calcium Chloride, and 1 gram Magnesium Sulfate per 20 gallons with a conductivity of 65-100mS. The 200 gallon rating is at 60 psi. In the summer, I was getting nearly 275 gallons per day as my incoming water pressure is 110 psi. I have to restrict the water pressure to 90 psi as the membranes are guaranteed to 100 psi.This system is made by Aquatic Reef Systems and I am very pleased with it.

I use this unit in conjunction to 2 Reo Pure 100 gallon per day units without a DI. It ha stwo high pressure Dow membranes. These are high end R/O units to be sure. These units came with a booster pump ( not really needed ) I operated these at 140 psi. and had good production of product water.

The three units have backflush valves which extend the life of both the membrane and deionizer cartridges. They are backflushed for approximately 1 minute every 600 gallons.

Joe ;)

Thanks a ton for that info Joe

Now I have a real clear understanding.
Last question if I may.:-)
Do you regenarate the anion and cation yourself or can that be done somewere ?

Thanks
Ronald

[roger]

Hello All

Im working hard at cutting the tap and muriatic acid out of the equation.

I finally put all of the pieces together for the RO unit. One of the pieces was a standalone canister that normally holds a DI bed. Instead DI put peat in it. The original thought was to try that on the tap water, but it works well enough on the RO.

So I have hooked the RO output up to the peat canister and its does help. Ill be tweaking that setup some to see if I can get there in one shot. The water comes out about 6.7 and with airation its dropping to about 6.2 or so.

I may ask walter to build me a 3 chamber unit with bypasses so that its easy to change out peat.

To ge the trace minerals back into the water Im going to be using "Instant Ocean" at 1tbsp to 10 gallons.

Ronald, that would be extremely difficult to regenerate the resins if not impossible. they are placed within a canister. Regeneration of mixed bed anion and cation resins is difficult. Lye is used( that's right--Drano )-then salt. i myself have never done it, but one must separate the anion and cation resins. One is heavier ( less buoyant than the other ) I just am not at all comfortable with the lye.

The cartridges cost me $ 16 each. Joe :)

Joe
I remembered that in the early 80's a friend of mine in germany had a cation - anion exchange.
the tubes were about 1 1/2meter high and 5 inch diameter.
I dident know that that was actualy a DI though, just remembered that it was a real hassel to regenarate that thing. Just bying new ones was out of question because they were abot 150 german marks wich was that time around 70 us $ per piece.( I think)
With your cost ther is no question what to do.

Againg thanks for the info.

Ronald

Ronald, If it the same german manufacturer, Peter Thode from Gwynnbrook Farms in Baltimore used to import them in two sizes--the largest being what you reference. The smaller one was about 15" tall. the gentleman passed away and the son and daughter were going to take it on. They had problems with gettin g the resins along with exporting --so they surrendered. Using DI by itself, the ersins are exhausted quite quickly. Joe