Treated Tap Water or R/O water?

[ghostie]

O.k.., when I first started 2 years ago, I just used tap water. It's free (relatively), throw in some dechlorinator and you're good to go. My water is pretty hard around here and after a few months, I had lots of algae - lots and lots of algae.

The LFS said go with R/O. I tried that and my algae problem cleared up. The fish seemed to like it also. It's not super expensive - $.25 a gallon, but it is a pain to go to the local water store to buy it (with the big tubs).

What do you all think? is it better to have R/O water or tap water? Assuming cost is not an issue - which is better?

I also read somewhere that R/O water needs to have something added to it (which I have not been doing).

thoughts?

 

[newfound77951]

Your tap water probably has higher levels of phosphate and nitrate, which would cause algae to grow. Since you have hard water, adding some RO water is OK, but you don't want the tank to be pure RO....there are no ions in RO, which would cause your fish to eventually have problems regulating their electrolyte balance. You DID read somewhere that you have to add "something" to the RO water.....those ions, or electrolytes. The easiest (and cheapest) way for you to do this is only use the RO water for part of your water changes. Use your regular (dechlorinated) tap water for the rest. What proportions of each you need to add will be a little bit of trial and error...you want to add as much tap water as you can without causing algae. A good phosphate and nitrate test kit would be a big help here, if you already have them, test your tap water for N and P....I bet they're pretty high.

 

[tropicfishman]

R/O is the best you can really get, I'dsave and buy one for myself though

 

[ghostie]

O.k., this is why I'm confused. One person says, mix tap water and R/O. The other says R/O is the best and implies that I should only use R/O.

I checked the nitrates of my tap water and it's 0.

I'm so confused.

 

[newfound77951]

Your algae problem is most likely due to phosphates....if you don't have a phosphate kit (not likely if you don't have a planted tank), take a sample of your tap water to your LFS, and they'll test it for you. If those aren't high either, then your hard tap water could be supplying enough micro nutrients (such as iron) to allow the algae to grow.

There have been a couple of other threads on here lately about the RO/tap debate. I think the confusion comes in between SW and FW tanks....on a SW tank, using only RO/DI to mix with the salt is the best way to go. Because you are adding salt, all the proper electrolytes are added back in. But DO NOT use only RO or DI water in a freshwater tank please!!! It is bad for your fishies! If you drank only RO water, eventually you would get sick from electrolyte imbalance....that's why you get a dilute saline solution in an IV at the hospital when you are dehydrated, not pure water.

Trust me on this one....I'm an oceanographer, I deal with critters and nutrients in water for a living! If it still doesn't make sense, please ask more questions!

 

[Apocalypse_Gold]

If you go 100% RO you will need to add something to replace the missing dissolved solids. I use all RO water because my tap water is very unpredictable and occasionally killed my fish (even when mixed 50/50 with RO water). I add Kent RO Right, baking soda for carbonate hardness, and some aquarium salt. If you want to buy your own, watch for a good deal on Ebay. My brother got the same one I have from the same place but mine was around $35 cheaper.

 

[ghostie]

All right - you all freaked me out so that I took about 3 gals of water out of the 18 gal. tank and replaced with treated tap water. I also threw in a handful of aquarium salt. I guess I'll go looking for R/O right. It's too bad petsmart doesn't have it. What does the baking soda add? It seems like R/O right is enough for everything (according to the Kent website) at least.

BTW, what is better the powder or liquid RO right?

 

[An t-iasg]

I used to mix RO and tap water half-and-half. I didn't really measure; I just filled an empty gallon jug about halfway with tap water and then filled the rest with RO water. I didn't do it to get rid of algae, but to lower my very high pH a little.

Your tap water nitrates are 0. Did you get a phosphate reading at the lfs? Since you say you had lots of algae, then what Newfound says is my hunch too - your water either contains too many phosphates or some other mineral like iron in a high enough quantity to promote algae. (I dose iron fertilizer in my planted tank, but only a drop or two a week.)

Since you said your algae problem is bad, you could try mixing half tap and half RO. That is the highest ratio I would mix - in other words, I would not use more than 50% RO water in the tank. The 50% of tap water will supply your needed electrolytes.

If this half-and-half mixture is not working for you, and algae still returns, then go with all RO water. Follow the other advice also to use an additive like RO Right. I don't know which is better - liquid or powder, since I never used it. I do use a powdered buffer from the Seachem line and it dissolves easily.

Apocolypse Gold adds baking soda to increase carbonate hardness since he has a planted tank and injects CO2. (Correct me if I'm wrong! ) I also have a planted tank and add CO2 but instead of baking soda I use the Seachem buffer that I mentioned, which I think is pretty much baking soda. Increasing the carbonate hardness in this way stabilizes the pH, which is healthy for the fish - they need a stable pH. If you don't inject CO2, ghostie, you may not need to add an additional buffer like baking soda. But you should test your mixed RO water and the RO Right for carbonate hardness, or ask your lfs to do it. For a non-planted tank, I think a carbonate hardness (KH) value of about 4 is fine. This will keep your pH stable. A lower KH value will probably cause pH swings, which aren't good for fish. If you see your pH is getting too low during the week, you may want to supplement the RO Right with some baking soda like Apocolypse does. The more heavily stocked you are, the more you may need to add the baking soda. If your KH test result of your RO Right water is 4 or above already, then you probably don't have to worry about baking soda.

Here's a good KH and GH test kit:http://www.aquariumguys.com/hardnesstest.html

 

[Lonewolfblue]

All right - you all freaked me out so that I took about 3 gals of water out of the 18 gal. tank and replaced with treated tap water. I also threw in a handful of aquarium salt. I guess I'll go looking for R/O right. It's too bad petsmart doesn't have it. What does the baking soda add? It seems like R/O right is enough for everything (according to the Kent website) at least.

BTW, what is better the powder or liquid RO right?

Now why are we just throwing in salt? Salt is unnecessary. Tap water is all you need. RO is primarily used in SW. Unless you have extremely high kh and gh, you don't need it. What is your kh and gh? And ph?