RO, How much to add?

[ryannxs]

have been aving issues with my tap water recently and have decided to buy some ro. its on its way to me as we speak but i have been reading some posts that suggest not add pure ro directly into the tank.
questions:
1: would adding pure ro be an issue if doing a 10% water change
2:if i mix my ro with my tap how much of each should i add for example 40ro60tap?
3: lets say i have mixed my tap and ro to "optimum consistancy", whats the largest percentage of water i could change?
4: if adding pure ro into a tank in small quantities is advised, is dechlorinator needed?

thanks guys, hope to hear soon, water should be here in 10 mins!

 

[Lornek8]

1. The reason not to add pure RO into your water is that RO is too pure. It doesn't have enough additional minerals to stabilize it & allow it to support life. Adding pure RO to your tank, even with just 10% changes will cause your tank parameters to change with each water change and eventually bring it very close to RO water whcih could be bad. If your trying to get your tank parameters to a specific value though, this could be a strategy to employ.
2. It depends on the values of you tap water. People mix varying ratios depending on the values they are looking for in the final mix.
3. 100% if you so choose. Depends on how different "optimum" is from yuor current tank parameters though. The same considerations need to be taken into account with simply changing any quantity of water irregardless of the source.
4. No declorinator is need, the RO process (usually with carbon prefiltration) removes clorine.

 

[L777]

Hi,

Pretty much agree with the above from lornek8 but I'd like to throw in my two penny worth for what its worth.

Pure RO is devoid of everything and therefore acts like a sponge when mixed with more 'normal' water and the chemical changes can therefore be quite rapid. So if adding large amounts of RO to an established tank during water changes the actual rate of change isn't good for the fish. The fish will probably easily adapt to whatever conditions eventually prevail but just like when bringing fish home from your LFS they need a period to allow there bodies to adapt to changes. That said more often than not you don't need to wrap them up in the proverbial cotton wool either. But when talking about rare and expensive fish one can never really be to careful.

I would personally recomend that you cut (with tap or HMA water) or remineralise the RO and bring it up to tank temperature (or maybe a few degrees below) before adding, wherever possible. It just reduces the stress that you'll place on your fish and that can never be a bad thing.

If your going to cut with tapwater you'll first need to know two things. The hardness that you are aiming for and that of the tapwater coming from your supply. Then its just a bit of simple math to work out the ratio for your specific requirements. i.e. if my supply has a GH of 20 and I require the tank to be GH5 then I add 1 part tap to 3 parts RO (25-75). Similarly if the supply is GH10 and I require GH5 the ratio would change to a 50-50 mix.

But you'll need to remember that the tapwater may still have chlorine/chloramine present and therefore will have to be dechlorinated.

Either mixing with HMA water or chemically remineralising is a far superior method of using RO as niether method reintroduces any of the 'nasties' that your trying to eliminate by switching to RO water in the first instance.

Remineralising chemically at first may sound a bit scarry and daunting but with the correct kit and once understood its childs play. It allows the end user complete control over all water parameters and is personally my preferred method. Partly it has to be said that it means I don't have to have a seperate HMA filter as well as an RO one and all the costs that that intails but also because of the absolute control and ease of replication it offers me.

You can buy off the shelf remineralising mixes but they are way overpriced for what they actually are or you can just do a few google searches find out what chemicals you need and simply buy them off ebay. A good set of accurate scales and you have all the reminerising kit you will ever need at a very resonable overall price.

Chris.

 

[Irene0100]

I agree generally with the above but will add my bit IMHO - I would not dream of 100% tank w/c, as will shock fish and remove useful microbes. so better to change 10-20 % per day until you have the dilution you want, it helps to buy a tds meter from ebay usually about £20 ish. to see how dilute the water is.

if you are getting RO from another person thats fine, if you are buying an RO unit to make your own RO then dont forget to stand the water for some hours before using so that CO2 from the air can dissolve into the water first,

 

[rickyjjuk]

I am no expert with RO water but can you not use it if you add Kent RO right or something similar????

 

[L777]

I am no expert with RO water but can you not use it if you add Kent RO right or something similar????

Hi,

Yes this would be one of the remineralising mixes I was referring to.

For the record I wouldn't advocate 100% water changes either unless in very extreme circumstances where you pretty much have no choice.

Chris.

 

[rickyjjuk]

Yeah I would never do 100% water change either. I normally do 15-25% every 2-3 days and have noticed my fish being a lot healthier.

 

[macvsog23]

5% twice a day on my tanks

 

[macvsog23]

http://www.plecoplanet.com/forum/showthread.php?t=11157&highlight=water
The above may help

 

[mikebren12]

OMG - was just about to start using RO water for my water changes, so let me get this right, if I do a 10% water change but use only RO water could I be doing more harm than good, currently I do a 10% water change once a week using treated tap water.

Would It be better to mix say 5% RO and 5% treated Tap water, or should I not get involved with it at all?

Im glad I saw this post, wouldn't want to hurt any of the fish!!!

Mike

 

[Lornek8]

OMG - was just about to start using RO water for my water changes, so let me get this right, if I do a 10% water change but use only RO water could I be doing more harm than good, currently I do a 10% water change once a week using treated tap water.

Would It be better to mix say 5% RO and 5% treated Tap water, or should I not get involved with it at all?

Im glad I saw this post, wouldn't want to hurt any of the fish!!!

Mike

It all depends what your intentions are for using RO water.
Is it to get your tanks to particular parameters?
Is it to simply provide the purest water you can?

These questions need to be investigated to best provide a meaningful answer. Some here say never use tap and only use only water that has been processed by some means (RO, HMA, etc).

 

[mikebren12]

It all depends what your intentions are for using RO water.
Is it to get your tanks to particular parameters?
Is it to simply provide the purest water you can?

These questions need to be investigated to best provide a meaningful answer. Some here say never use tap and only use only water that has been processed by some means (RO, HMA, etc).

Hi Lornek,

It was really just to as you say provide the purest water possible, and I thought as I had access to free RO water a 100yds down the road seemed like a good idea?

Mike

 

[L777]

Hi,

To be fair mikebren12 a lot of the questions you asked have already been answered in this thread. Just have another quick read over whats already been written.

There is a lot of difference between tap water supplies in differing areas and some water authorities supply water out of the tap which is pretty good. If your fortunate enough to live in this kind of area then you may not need to do anything. However the water from my tap is often referred to as liquid concrete its so hard and the TDS is pretty high also. So to keep Amazonian species its best for me to use RO water.

You can't make any really informed decisions about which course is best for you to take until you know the quality of your tap water supply.

Chris.