Using RODI water to lower pH in stocked aquarium

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jlbfish

jlbfish

Aquarium Advice FINatic
Joined
Feb 21, 2012
Messages
806
Location
Texas
What is the process on lowering pH by slowly adding a mixture of RODI water and tap water. My pH is 7.8 and my C Hasbrosus are dying off slowly. Hoping this will help. Tank is cycled water parameters are normal.

Stocked list:
4 Threadfin rainbowfish
6 c Hasbrosus (started with 11). :(
6 neon tetras.

I've lost 4-5 tetras over the last 8 mos but over the last 4-6 weeks I've lost 5 Cories. Would like the others to thrive.

Considering following the instructions on pH down no more than .2 in a 24 hr period
 
If your water is at a stable 7.8 pH I am not sure this is the issue - Did you buy your fish locally?
 
It's stable. I did buy them locally. Waiting for the store to open so I can find out if they are wild caught. From what I have seen 7.8 is high for C Hasbrosus their profile is 6.0-7.2. I figured they would acclimate but I'm losing 1 a week in a stable tank :/. Other than bad stock not sure what else to try.
 
Once you start using RO you are going to have to keep monitoring the water to keep it stable. It is not easy to do, I had to do that in the beginning with my 220g until my mostly peat organic soil started lowering the ph naturally. But I still have to monitor it carefully. One thing you can do is add peat to you filter but depending on the size of the tank you might need to add quite a bit. Another thing is Indian Almond leaves. They will however color your water with tannins which many people don't like. But the leaves also have anti-bacterial and anti-fungal properties which is another plus. If you want to do the RO then you have to drop the PH slowly, very slowly so you don't PH shock your fish. Don't know what size your tank is but when I did my 220g I took out 10g of tank water each day and replaced it with 10g of RO water. It took 4-5 weeks to bring it down but I did it slowly and safely and had no problems with the fish adjusting. Personally you can do this but I'd look into some IA leaves and get them in now, just put up with the tannins for a bit while lowing the ph with RO. Don't use any PH adjustor chemicals as they are only a temp fix and can do more harm than good.
 
When you say monitor it to keep it stable how often do you test and what do you do if it starts to crash/spike?

Almond leaves add tannins. Does that pass like driftwood? Right now the tank has tannins from a piece of wood I added a few weeks ago so I don't mind them as long as it passes.

This is for a 28 gallon tank. We have a filtration system for drinking water and I tested the ph of that (it didn't sit out for 24 hrs) and it was 7.2 on the High Ph and 7.6 on the Ph test. How does that read to you guys?

I assume the IA Leaves lower pH over time? Shouldn't I wait for those to lower as much as they can before I start using RODI?

Thanks all!
Jana
 
I monitored KH and GH. I wanted mildly soft water with a KH and GH of about 4. With those numbers there was still enough calcium and magnesium in the water to stablize the ph. My ph fell to about 7.0 which was fine. Its the GH/KH that makes water soft or hard. When my water came down to those readings I wasn't worried what my ph number was. API makes a test kit 2 in 1 for KH and GH. Two seperate tests not one test that reads both.

As for the almond leaves tend to leech less and less as they dissolve. A ph reading of between 7.2 and 7.6 isn't too bad as fish usually acclimate to it. Personally if it were me I think I'd try the Indian almond leaves and/or peat in the filter before messing with RO. I would however get a GH/KH test kit so you can see what those readings are.
 
Ok I got the KH/GH test kit. I have no idea how this plays into the pH other than making it more stable? Anyway my KH is 8 degrees and my GH is 57.3 that reads in between two results but both of those results are for Tropical Fish. Iw would assume my Threadfins and Neons are fine in this. Problem is the Corydora Hasbrosus that I bought were caught wild. SO they don't like a higher pH. BUT at this point I am thinking that there are 6 of them left. I may just leave it alone and go to 20% water changes as needed either weekly or biweekly. The water going into the tank could have a pH shift and changing 50% of the water could be too much of a swing for them.

Thanks for all of the help!

Jana
 
jlbfish said:
Ok I got the KH/GH test kit. I have no idea how this plays into the pH other than making it more stable? Anyway my KH is 8 degrees and my GH is 57.3 that reads in between two results but both of those results are for Tropical Fish. Iw would assume my Threadfins and Neons are fine in this. Problem is the Corydora Hasbrosus that I bought were caught wild. SO they don't like a higher pH. BUT at this point I am thinking that there are 6 of them left. I may just leave it alone and go to 20% water changes as needed either weekly or biweekly. The water going into the tank could have a pH shift and changing 50% of the water could be too much of a swing for them.

Thanks for all of the help!

Jana
Click to expand...

What that shows is your you have hard water, if the cory's are wild caught they were most likely in very soft water (which is your kh/gh) When you lower your kh/gh to soften your water the ph naturally drops. All my SA cichlids and tetras do good at a KH and GH or around 4. That also leaves enough minerals in the water to keep the PH stable. You could do two smaller water changes weekly using about 1/4 of the water you replace with RO. This will slowly drop the PH and might help them. But when doing that you need to watch that your KH/GH doesn't drop much past 4. The Ph will drop and stablize at a lower number. Then you have to figure out once your numbers are where you want them how much RO to Tap it takes in weekly WC's to keep your KH/GH where you have it. Another thing that could be really good for them is to get some Indian almond leaves and use them in the tank. They will release tannins that will help soften the water plus they release anti-bacterial and anti-fungal properties into the water. There are also blackwater extracts you can buy but I like the IA leaves.
 
It does get confusing! You still have a fairly high KH even tho you have low GH. And from my limited understanding the higher KH which is alkalinity is what keeps your PH higher. Honestly I'd try using some type of blackwater extract or the indian almond leaves. My fish (angels, tetras, rams, corys) all get really perky when I add new leaves. That might just give the remaining cory's the extra boost they need to fully acclimate to your tanks water. And then you don't have to worry about trying to adjust your water.
 
OH ok I think I get it. So the RODI reduces the KH which allows the PH to fall. It isn't necessarily adding water of a lower pH.

How long do the Indian leaves work in the water? how often do you replace them?

Thanks again!
 
Yep that is the basic priniciple but RO water also has a lower PH because RO water has a 0 KH/GH.

What size is your tank? Depending on the size of the leaves you get (they can be up to about 8") will determine how many you use. The best way to do it is put one in and wait to see how dark your water gets by the next day. If you don't mind the color you can add another. Many people replace them as they breakdown but I leave them in my tank until the leaf is just a veined skeleton because my oto's, bn pleco, and the whiptail cats all like to munch on them. I usually add new leaves about once a month or as needed by how old leaves are looking. If you have any rams in your tank they will many times spawn on the leaves.
 
It is a 28 gallon bow

Nope no rams :) But Threadfins, Neons and Hasbrosus.

Does it color the water permanently? or just for a period of time?

Shouldn't the Distilled water also have a lower pH or is that not the case because it probably isn't 0 GH/KH. The Distilled water I tested was not neutral if I remember right it tested at 7.6, I know it was definitely above 7.0
 
I know distilled water is different from RO water but don't remember why. I don't mess with DI so don't really know. I have my own countertop RO and if you read up on RO's all properly maintained RO's should produce 0 KH/GH but the PH of the RO water will depend on how high your taps PH is to start with. My tap is over 9.0 PH and it brings my RO PH down to the 7.0 range.

As for the IA leaves they start off leeching alot then get leeched out and as you do weekly WC's the water color fades. The leaves are perfect for the kind of fish you have. Threadfins included (I have 12 in my 220g).
 
Ok. I think I having pH swings I wonder if it is from over feeding Pygmy Cories

Anyway I swear I tested yesterday and it was 7.4 because I was thinking of dropping the whole thing. Today it is an 8.0 which seems dangerous enough to kill some fish I haven't water changed yet because of the pH issues but now I'm thinking I need to stabilize more than change.

Does the 8 degree KH make pH stable or unstable. ? Off to read more on water chemistry. :(
 
With your KH your tank ph should be stable. You don't have alot of fish so you shouldn't be feeding very much. I might use about an 1/8th of a teaspoon of food daily for my 220g. I'd still use the leaves and just monitor your readings and don't drive yourself crazy.
 
Lol will do. Going to the LFS today to see if they have any :)
 
You will probably have to order them on ebay. I've never seen a store that actually carries them.
 
Thanks for the heads up! The LFS is quite a drive. I called and they have them. Yay! I'll head down tomorrow and get them and some new Corydora Trilineatus for my 75! :)
 
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