Reverse Osmosis Question???

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AQUA_OBSESSION

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Dec 12, 2005
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Hi Everyone, I have a pretty basic question regarding Reverse Osmosis. The water quality at my house is pretty bad, the water is very hard and the ph is right around 8.3 or so. I set up a tank a few years ago and it did not go so well. In my previous residences I have never had a problem with water quality and keeping fish, but here is a different story.

This time around I purchased a R/O filter from my lfs because I wanted to correct this problem and do it right this time. My question is this.... Why would my water's ph still be in the 8.3 range after it has gone through the r/o filter? I thought this filter was supposed to remove just about everything from the water and that the ph should be around 7.0 or so. Am I incorrect to think that this filter would do this? or is my r/o filter possibly set up incorrectly? It is a 75 gpd output - but it is much slower than that. I have heard that if the water quality is really bad that the output would be less than the 75 gpd.

I was hoping to get discus some day but am worried about the ph being so high.

Any help, feedback, etc would be greatly appreciated.

AQUA_OBSESSION
 
Do you have enough water pressure to run the RO unit? Should be around 80psi. Is your water coming from a well? If you recieve city water, your cold faucet should be on ALL THE WAY.
 
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Yes your Ph should be around 7 after the unit. the membrane is rated at 75 GPD (in optimum conditions), meaning water preasure around 80 psi and water temp of about 77 degrees. Chances are if your not using a booster pump your input's only around 40 psi (estimate) and your water temps around 56 degrees. So don't be suprised not to see 75g per day. As for your hopes of keeping discus as long as your pH is below 7.5 you won't have any issues. The hardness (TDS) is what's important and you shouldn't have any problems mixing your RO with your tap to achieve proper discus water.
 
get a cup of the r/o water and aerate it overnight...age it and see what the pH is after 24 hours of aerating. I bet the pH drops. As far as discus, you can keep them in a pH of 8.3, but they would be just a tad bit happier in a slightly lower pH range. See what the pH reads after you have aerated it overnight. And for hardness and discus....it doesnt matter. I know people who keep discus in a hardness of 15GH and as low as 1GH...it doesnt matter as much as everyone thinks. The only reason why you would want a lower hardness is for breeding purposes ONLY.

-Ryan
 
wwildcats04 said:
did you get it at petsmart? if so its a water purifier not a RO unit
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My money is on this theory. The reason being is b/c I never used to run a booster pump running about 30psi and the Ph still came out around 6.8 with original water ph of 7.9 or there abouts.(the reason I got a booster pump was b/c it was just to slow in making the water)
Dkarc said:
get a cup of the r/o water and aerate it overnight...age it and see what the pH is after 24 hours of aerating. I bet the pH drops.
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If you aerate the water the PH will rise, why is this? B/c the objective behind aerating water to get a stable ph reading is to disipate Co2, and if you disipate Co2 the ph will rise.

I don't think you RO machine is a RO machine or you have installed it incorrectly.
 
i had a similar problem,

my tap water changed ph mid fall from 7.4-7.6 to...well the ph color card stops at 8.8 and that's the color the water tests. so i realize its probably higher than 8.8. i assume its extremely Co2 depleted because of the cold weather. its also extremely hard water......

so i decided to mix, or cut, it with RO water from wal-mart. but the RO water tested exactly the same!!! making me question whether or not its truly RO.
maybe the temp, is still affecting Co2 levels?

so...i aged it

as an aside: aging water isn't just to release Co2. its to balance it with the atmospheric Co2
so the ph will only go up from aging the water if the water has more Co2 than the atmosphere. if it is depleted of Co2 it will drop.

anyway...after 24-48 hours the Ro dropped to 7.0 (the tap dropped to 8.0)
i mixed them 50:50, waited an hour and it was 7.8
waited 48 hours and it was 6.4-6.6!! so maybe the RO dropped more. (i've aged the tap for longer before and can't get it below 8.0)

so now i've got it mixed-up in a 5gal container with 3gal tap and 2gal "RO" waiting another 24-48hrs to see what that is.

i don't know if that applies. but it should drop if you age it. but....i don't understand why we have to do that since RO is supposed to be 7.0 or lower. and i would think forcing it through i membrane would sufficiently gas it.

:huh:
 
You guys rock!

Thank You everyone for your feedback. Once I saw the overwhelming response to my post I went down and really played with my R/O filter. I printed off the directions and read it over several times. I noticed one thing that may have seemed like a minor detail but it ended up being the difference. I have a Coralife Pure Flow II R/O filter and the membrane has a black seal (o-ring thingy) about 2-3 inches from the back of the filter - it is taped on there with blue electrical tape - well it came loose when I was putting the filter in. There was only a small piece of tape holding it so I did not think it was a big deal. As I looked at the diagram I noticed it was taped to the membrane a few inches below and figured that was the problem. I re-taped it with black electrical tape and decided to run it again. I just completed a 5 gallon bucket of water and went down to test it - and low and behold the ph was 6.5. I am pumped, finally it is working right. :dance2: :dance2:

THANKS AGAIN.... I hope to some day help others out like this.

AQUA-OBSESSION
 
great :thm: Im glad that everything worked out for you, its so frustrating when you buy a piece of equipment and you cant figure out how to work it at first.. this is what happened to my diatom filter that i've only used once... I prob wouldnt be able to get it started again
 
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