RO Water and pH

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An t-iasg

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I got RO water the other day. I got it from the machine in my grocery store. I didn't do a water change with it yet. I wanted to test the pH first. The pH of the RO water is 6.6. I mixed it with tap water and tested again. The pH was 7.4. That's the highest my kit goes up to. If I do a pH of plain tap water, it's darker blue than the 7.4 blue. I should get another test kit so I know for sure what my tap water pH is. But even mixing with the RO water, the pH is still high. So, lowering the pH isn't going to be as easy as I thought. I'm trying to get away from the pH down products -- any ideas?

Also, I saw a mix for RO water in my DrsFosterSmith catalog. It says it has the perfect mix of salts and trace elements to balance RO water. Does anyone use anything like this? I guess that's why you use RO water and tap water together, so you still have the beneficial salts and other elements of tap water. It's probably overkill to use this product in my small tank, but I'm trying to learn all I can!
 
... You tap water has very high Alkalinity. You need to decide @ what ph all your fish are going to be comfortable at. Don't bother getting a test kit for high end ph. Unless your keeping cichlids or the like the ph is going to be to high for most fish anyway. Most FW tropical fish prefer lower ph. If the tap in your area is as bad as it looks, I would suggest the use of R/O water(maybe even investing in an R/O unit) R/O water is much softer, so the ph is going to be much lower from the start. The mix you saw in the DrsFosterSmith catalog is to replenish trace elements to tank water. When water is filtered through an R/O unit it removes much of the neccessary trace elements. These electrlytes are needed by your fish as well as live plants. So if you start using R/O water your going to need some trace elements. Kent makes some and Seachem makes some. I should warn you though if you have live plants and you're using CO2 injection of any kind, the ph in your R/O water will drop like a rock. You will have to add Carbonates to buffer against ph swings. I know it looks complicated, but it's not really. R/O IMO is much easier to use, since adding in the appropriate traces is a piece of cake.
 
This is a very tricky thing to do, but many, many aquarists do it regularly. However, be certain it is necessary before you get into the chore of maintaining your water in this way. Every water change must be carefully monitored to keep the pH stable. My fish do well and spawn in 7.4 or 7.6 pH, which are tetras and angels, and white clouds. Do get the high-range pH test kit, which will give you a better idea where you are. Here is a great article on RO water basics: http://fishgeeks.com/modules.php?op...e=article&sid=305&mode=thread&order=0&thold=0
 
Thanks, guys! I would like to add a java fern, but for one plant in a 5 1/2 gallon tank, I'm not going to get a CO2 system. I would rather have a stable pH without using the pH down drops. Even using the drops, the pH does fluctuate a little, and I read that it isn't uncommon when using those products to have a rebound of some sort. We have been thinking about getting an RO system for the house. It would save us buying and lugging home a bunch of bottled water jugs!
 
An t-iasg, I also use r/o water from the store. The thing to remember about r/o water is that it has very little buffer ability, so any buffers added at all will affect the pH of the water. I use r/o water in my 10 gal black water tank, and I mix some stuff called electro right, which is the same thing as r/o right. According to the directions, adding the stuff to r/o water gives it a pH of 5.8. Adding more gives a pH of 7.0. I've been using it for a while, and haven't lost a fish in a while, in my amazon tank anyway. Which brings me to my next post...
 
R/O really ISN'T that hard to work with. I really think it's easier since you start at a point that is closer to where you want to be. Adding in trace elements is a piece of cake. You do need to test for gh though, make sure you have a test kit for it. Again I wouldn't advise getting the high range kit unless you are keeping fish that require hard water. You have such a small tank to maintain. Just remember to test for GH so you don't over do the traces and when you water change you will have to replace those traces.
 
Hi James,
Do you mean RO really is not that hard to work with?? It seems like mixing it with your tap water is the hard part., to get the right pH every time you mix. I'm using the pH down drops now, but I know that can be unstable, and I want to add a plant, and I read that plants can cause pH instability too. Now probably in my 5 1/2 gallon, 1 plant isn't going to really matter. But small tanks can crash easier than big tanks too.

Anyway, I think I will use all RO water and not try to mix it with the tap water. I will add the trace elements as you guys have suggested; it can't be that hard to do! I see RO Right from Kent, Equilibrium from Seachem, Electro-Right from Aquarium Pharmaceuticals (? can't quite make out the small picture) in my catalog. They all look like what I need. Maybe I'll choose the Seachem since it says for planted aquariums. I know that one plant is different from a planted aquarium, though. Shawmutt, do you have plants in your tank?

GH -- general hardness -- I don't have a kit for it but I'll get one. Is this so you can tell how much of the mix to add and don't overdo it? Plain RO water doesn't have any hardness, right?

Any tips on how to gradually change over to the RO water? I change a gallon of water a week. Is that gradual enough? Then it would probably take a month for all the water to be changed over. Should I wait until then to get the plant?
 
Shawmutt, do you have plants in your tank?

Yes, I have a bunch of Java fern and a sword plant, and they do fine by my method.

Plain RO water doesn't have any hardness, right?

right. one of the measurements in ro water is TDS, or Total Dissolved Solids. The water I get at Walmart is 6 TDS (or parts per million), compared to distilled which is 0 ppm and rain and snow which has 10 ppm. It's pretty pure water, and the normal tests we use for aquariums should not pick up any hardness.
GH -- general hardness -- I don't have a kit for it but I'll get one. Is this so you can tell how much of the mix to add and don't overdo it?
Well, to be honest, I have a gh kit and a kh kit, but I rarely use them. I find that as long as the pH is equalized, my fish do fine. I just follow the instructions on the bottle for the fish I have.
 
An t-iasg said:
It seems like mixing it with your tap water is the hard part., to get the right pH every time you mix.

An t-iasg, its really not hard. I mix water for my 30 gallon tank. I mix the water in a 5 gallon bucket (2 gallons RO, 3 gallons tap) and test it to make sure the KH is where I want it (between 4-5). If the KH is where I want it, the PH is always in the range that I want (7.4-7.6) but I test it every time just to be sure. As long as my KH stays at 4-5, the water is buffered well enough to keep the PH in the tank stable.

If you want your PH lower than that, mixing the trace elements in is probably a better way to go as it sounds like your water is similar to mine--quite hard. I would highly advise testing your KH though to make certain it is well buffered, as sufficient KH is what keeps your PH stable. I don't think I would be comfortable any lower than 3-4.

I tested for GH in the beginning but I don't test it regularly. You are correct in that RO has no (or very little) hardness.
 
I have a similar problem as you An t-iasg. What I do is use RO/DI water mixed with my tap water to provide me with the proper level of GH & KH. For me that is between 4-6. I don't worry too much about PH at that point.

Then after I get the proper mixture I use a PH regulator like Bullseye 7.0 to set the PH at 7.0. It will accomplish what your PH down drops do but will keep the PH at 7.0. Just be sure to add the proper amount of Bullseye 7.0 with each water change to avoid diluting it and you'll be fine. I haven't had a problem yet using this method. :)
 
Good old government guys, my tap water kh/gh used to hover in the 6-7 range.
Test this weekend showed the kh at 7 but the gh is up to 11. and ph of 7.1.

The area switched to a brand new water treatement plant 8-(.
 
Thanks for your help, everyone! Lots of great advice! :D

So, when mixing tap and RO water, or using RO and a mix, the thing to look for is the GH and KH. If they're ok then the pH should fall into the right place too. A product like Bullseye or Neutral Regulator will fine tune the pH without the need for the pH down drops. Right?

I'd like my pH to be 7.0 or 7.2. Since a half & half mix of my tap water + RO was still about 7.4 - 7.6 pH, I think I'll go with all RO water and add one of the RO mixes. We have been thinking about getting an RO unit anyway. Our tapwater isn't that bad to drink, I don't think, but my husband hates it and we always get bottled water.

So I'll also need a KH/GH kit. Some of you have said that your preferred KH/GH is 4, 5, or 6. How do you know this? Can someone explain the basics of KH/GH or provide a link?

Once again, thanks!
 
In addition to my GH/KH questions, I have another one: For those of you with RO units in your house, do you have to get a holding tank, or would it work without one?
 
Hi Shawmutt,
Thanks for the link. Unfortunately, it was unavailable when I clicked...hopefully it will be up later. I did find some sites and read them -- some were a little complicated! I ordered my RO mix today and when it comes I'll go to the grocery store, get the RO water, and try it! I also ordered a GH/KH test kit, so I'm all set!
 
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