Remineralizing RO/DI water question

Just started using RO/DI water for my central american fish tank. Say if i am doing a 15 gallon water change does each 5 gallon bucket need to have the same amount of alkaline buffer and replenish added to it ? Or do i need to split up the alkaline buffer and replenish between the buckets to get the desired KH and GH for my tank? Forgive me if this post is in the wrong area or format this is my first post on the forum.

 

It does not matter how you do it as long as you get the GH and KH where you want in the tank.

What I do is I just add the water to the tank. Then I spoon the powders into the filter as needed.

 

if it helps at all it's by volume, you can mix each 5 gallon bucket exact, or one high, one low and then the 3rd whatever is left of the proper measure in total to get it where you want it or any variation of the mixing.

you'd get enough product to get it where you want it for the 15 gallons, how you mix it is up to you. Assuming it's a 75g and your're doing 20% water changes that are 15gs, that 20% isn't that critical for your GH or KH to stay where you want it, However if it were salinity, it would be less forgiving.

Frank the Fish guy adds it to the filter and lets the filter do the mixing. it works too. it's the "well under 2 dGH or dKH or the over 20 dGH or dKH" that are a problem to have. pH is gonna be stable as long as you have a couple degrees of KH minimum.

A little higher or lower in my opinion isn't critical just as long as you're within the appropriate ranges for the species you are keeping.

And if you happen to be trying to breed L046 zebra plecos, GOOD LUCK TO YA!

 

So my plan of action is going to be using a tds meter as i add my alkaline buffer to a 5 gallon pale until i reach my desired level, then put one cap full of Replenish in each of my buckets before adding the water back into my tank. Will that be too much replenish for 15 gallons or will that work?

 

to dose replenish, 1 cap = 100 drops. 1/10 cap = 10 drops.

10 drops treats one gallon, 100 drops treats 10 gallons,

should be 1-1/2 caps for 15 gallons. to raise the dGH to 2.8
1 cap per 5 gallons will be 2x as much and should bump your GH to 5.6 dGH instead of the 2.8 dDG. .

What are you trying to achieve?
I mean if your goal is to get into the 4-8 dGH range, yes, the 1 cap per 5 gallons will get your bucket water at 5.6 dGH per bucket.

If you were looking for 2.8 dGH, it's too much, and if you were looking for 9-12 dGH you want to do twice as much per 5 gallon bucket. Depends on what you are doing.

Also just going to say you can get a high TDS reading by dumping a bag of sugar in your tank. it doesn't differentiate between different dissolved solids. jsut measures all of them.
No idea how this works, but I'd assume if you only dose one with the TDS meter, and can cross it to what it means in dKH, then sure, No idea how it works, I'm older school than that.

Are you using the Alkaline buffer with an acid buffer for pH manipulation, or just to raise KH?

 

central american fish

Unbelievable this gets me out from my forum hiatus. (but only this once)
So we're talking livebearers and cichlids like Amatitlania or Thorichthys?

If so, why all that fuzz? They prefer hard water. 15-20° GH, more than 10° KH, pH around 8: All not a problem.

So if you are using an RO unit because of hard source water from the tap this is all redundant.

Also just going to say you can get a high TDS reading by dumping a bag of sugar in your tank. it doesn't differentiate between different dissolved solids. jsut measures all of them.
No idea how this works, but I'd assume if you only dose one with the TDS meter, and can cross it to what it means in dKH, then sure, No idea how it works, I'm older school than that.

You are correct, a TDS meter is not suitable for this. Instead a normal KH and GH test would suffice.

As well as doing the math. Miligrams per liter is much easier to calculate. 1° GH equals 17.8mg/l Ca/Mg, 1°KH equals 21.8mg/l HCO3 (hydrogen carbonate).
But as that Seachem stuff not only contains calcium and magnesium but also sodium and potassium, this is tricky.
Seachem as I love it. Useless by design.

 

to dose replenish, 1 cap = 100 drops. 1/10 cap = 10 drops.

10 drops treats one gallon, 100 drops treats 10 gallons,

should be 1-1/2 caps for 15 gallons. to raise the dGH to 2.8
1 cap per 5 gallons will be 2x as much and should bump your GH to 5.6 dGH instead of the 2.8 dDG. .

What are you trying to achieve?
I mean if your goal is to get into the 4-8 dGH range, yes, the 1 cap per 5 gallons will get your bucket water at 5.6 dGH per bucket.

If you were looking for 2.8 dGH, it's too much, and if you were looking for 9-12 dGH you want to do twice as much per 5 gallon bucket. Depends on what you are doing.

Also just going to say you can get a high TDS reading by dumping a bag of sugar in your tank. it doesn't differentiate between different dissolved solids. jsut measures all of them.
No idea how this works, but I'd assume if you only dose one with the TDS meter, and can cross it to what it means in dKH, then sure, No idea how it works, I'm older school than that.

Are you using the Alkaline buffer with an acid buffer for pH manipulation, or just to raise KH?

My goal is the 4-8 dGH range, and I am only using the alkaline buffer. Trying to keep this as easy and repeatable as possible.

Unbelievable this gets me out from my forum hiatus. (but only this once)
So we're talking livebearers and cichlids like Amatitlania or Thorichthys?

If so, why all that fuzz? They prefer hard water. 15-20° GH, more than 10° KH, pH around 8: All not a problem.

So if you are using an RO unit because of hard source water from the tap this is all redundant.


You are correct, a TDS meter is not suitable for this. Instead a normal KH and GH test would suffice.

As well as doing the math. Miligrams per liter is much easier to calculate. 1° GH equals 17.8mg/l Ca/Mg, 1°KH equals 21.8mg/l HCO3 (hydrogen carbonate).
But as that Seachem stuff not only contains calcium and magnesium but also sodium and potassium, this is tricky.
Seachem as I love it. Useless by design.

I have an RO/DI system set up for my reef tank and I cant use my tap water because it runs 10 ppm nitrate so I just use my RO/DI system for both tanks even though its not the most convenient.

 

It would be better to add your Replenish to one bucket and the buffer to the other. The reason is that Replenish contains calcium. magnesium and other metallic ions while the alkaline buffer has carbonates and bicarbonates. If you mix the two together in the same bucket, the calcium and magnesium will start to react with the carbonates becoming insoluble in water. Thus, keep them separated as long as you can. If you do get any precipitation, the water may become slightly cloudy, but it will eventually clear.

 

This is handy since it is one powder for both GH and KH at the same time.

https://www.sera.de/us/product/freshwater-aquarium/sera-ghkh-plus/

 

I have an RO/DI system set up for my reef tank and I cant use my tap water because it runs 10 ppm nitrate so I just use my RO/DI system for both tanks even though its not the most convenient.

I get that for the reef tank, but 10mg/l of Nitrate would be no problem in a freshwater tank. I have readings up to 40mg/l in my tap. That's for sure not suitable for a tank.
But 10... It's your money, not mine. *shrugg*

Good luck then.

 

I get that for the reef tank, but 10mg/l of Nitrate would be no problem in a freshwater tank. I have readings up to 40mg/l in my tap. That's for sure not suitable for a tank.
But 10... It's your money, not mine. *shrugg*

Good luck then.

Interesting, I always figured that even though the tap is 10ppm nitrate that over time the level inside the tank would become gradually higher with every water change? If this isn't the case then I'd much rather just use my tap and not worry about the remineralizing. Thanks for the insight!

 

Interesting, I always figured that even though the tap is 10ppm nitrate that over time the level inside the tank would become gradually higher with every water change? If this isn't the case then I'd much rather just use my tap and not worry about the remineralizing. Thanks for the insight!

Fishkeepers with saltwater aquariums often use RO water or RO/DI water to make sure there are no impurities in the water that might harm sensitive organisms like corals. It is a much less common practice for freshwater as freshwater streams, rivers, ponds and lakes are subject to varying concentrations of chemicals from rainfall, snowmelt, farm and forest runoff, etc.

I do use RO water for cooking, drinking, and aquarium use as my tap water is horrible. The water as received from the utility can vary from 19-28 dGH (325- 500 ppm hardness) and has a pH of 8.2. Furthermore, it is treated with chloramine. It does not taste good and it is not good for showering, washing clothes, etc. I have to have a water softener to replace the calcium and magnesium ions with sodium. However, that is not good either as I am on a low sodium diet and high sodium levels are not good for live plants in the aquarium. Thus, I find it better to use RO water with added minerals. However, I have had aquariums for over 60 years; I have only needed RO water for the past 20 years I have lived in this location. I would much rather use tap water.

By the way, I would suggest you remove the DI resin cartridge from your RO unit, or at least do not bother replacing it when it is exhausted. The resin might have some utility for sensitive saltwater aquariums, but it does little or nothing for freshwater aquariums. My RO membrane produces water with 10-20 ppm TDS. Most of that conductivity is probably due to dissolved CO2, which is not an issue. Water with a TDS of 0 ppm might be useful in a laboratory; but it is not needed for freshwater aquarium use. A DI resin bed is an unnecessary expense.

 

Interesting, I always figured that even though the tap is 10ppm nitrate that over time the level inside the tank would become gradually higher with every water change? If this isn't the case then I'd much rather just use my tap and not worry about the remineralizing. Thanks for the insight!

I see the error: The units denote a concentration of amount per volume of water, not an actual amount. It will not rise, but it will also not budge below that level. That's the only downside. Many people do waterchanges for ages and ask why their nitrates won't go below a certain level. Usually that level is the concentration of their tap.

With a decent amount of plants you might even get below 10mg/l. You should still do regular 50% waterchanges.

Depending on your GH and KH levels in your tap you still might want to push these levels up. Central American fish prefer "liquid rock".