Thinking of using RO

[Mr Gumby]

Hi folks, 

I've found a place locally that sells RO cheap enough that it's now a viable option for me to use. I can't justify a home unit for the volume I need.

Long term I'll be blending it with tap water at around two parts RO one part tap. Some testing needed to work out the exact ratio. Tap water is very hard with 20ppm nitrate.

Question is can I just do small water changes at around 10% weekly with pure RO until I get near the desired KH and GH or is it best to blend with tap from the start?

[Mmiller2001]

Small water changes with just RO is fine. Or you can blend and water change, the above will be faster, but the below is more stable. However, 10% increments is stable enough.

[Mr Gumby]

On 11/16/2021 at 11:40 AM, Mmiller2001 said:

Small water changes with just RO is fine. Or you can blend and water change, the above will be faster, but the below is more stable. However, 10% increments is stable enough.

Yep, I was thinking 10% wouldn't adversely affect anything but always best to get a second opinion thanks

[Gator]

@Mr Gumby; When I changed my tanks from tap water to RO/DI water, I changed 25% of the water so that now after many years, all of my tanks are 100% RO/DI and my fish and I couldn't be happier. Of course I added peat moss to my filter to make my water a little more acidic for my blackwater fish (That's all I have), and they still love it.

[Mr Gumby]

On 11/16/2021 at 4:04 PM, Gator said:

@Mr Gumby; When I changed my tanks from tap water to RO/DI water, I changed 25% of the water so that now after many years, all of my tanks are 100% RO/DI and my fish and I couldn't be happier. Of course I added peat moss to my filter to make my water a little more acidic for my blackwater fish (That's all I have), and they still love it.

@Gator in that initial change over were you remineralising from the start or as I'm planning let it fall to where you want it then add minerals?

[BenA]

On 11/16/2021 at 4:04 PM, Gator said:

@Mr Gumby; When I changed my tanks from tap water to RO/DI water, I changed 25% of the water so that now after many years, all of my tanks are 100% RO/DI and my fish and I couldn't be happier. Of course I added peat moss to my filter to make my water a little more acidic for my blackwater fish (That's all I have), and they still love it.

Please explain with more details.

I want to have a 300ltr. black water tank but my problem is that my tap water are PH 8, 40ppm nitrate and KH 20.

Do you add salts/minerals to the water? What substrate do you use? Do you keep plants? Which?

Thank you

Edited November 16, 2021 by BenA

[Gator]

@Mr Gumby; No I didn't add any minerals, the only things I add to my water is comprehensive ferts and iron for my plants, but thanks for asking.

The tap water here has a lot of Phosphates as well as other harmful chemicals, the RO/DI process removes the chemicals, but not all of the Phosphates and Calcium carbonate. The Ro/DI water has a pH of 6.0, but the hardness is up there so I use the Fluval Peat Pellets in my filter to make the water softer. It works very well.  

[Gator]

@BenA; Your tap water does have a high pH, the tap water here has a pH of 7.8, still too high for my blackwater fish. Your high pH and my high pH would be better suited for African cichlids or livebearers, but we don't want either.

As I replied to @Mr Gumby; I don't add chemical buffers to my tanks, doing so would pretty much destroy my desire for blackwater tanks.

My substrate is Eco Complete which has iron in it, but I still add more iron.

I have a grouping of Crypts in two tanks, a grouping of Hygrophila polysperma in two tanks, a Hygrophila difformis in one tank, a grouping of Juncus Repens in one tank, two Java ferns in one tank, a Java fern Wendlov in another tank, an  Ozelot sword in one tank, an Amazon sword in another tank, an Anubias nana in three tanks, a grouping of Bacopa caroliniana in one tank, and a Nymphaea lotus in two tanks.

My regrets about all of this is that I don't have the artistic eye you folks have so my tanks are pretty much rag tag. I also regret not having the space for the large sized tanks I had when I lived in Orlando, Florida, my largest tank here is 29G so I do the best I can with such limited space, but the principles are the same.

[Gator]

@Mr Gumby; I'm sorry I failed to mention that when I change water in any of my tanks, of course I change 25% of the water. In my 29G, this means removing 9G and replacing 10G due to evaporation, but it's how I replace the water that makes the difference.

When I start replacing the water, I'll put in 3G and then wait 15 min before I'll add 3 more gallons, then I'll wait 15 more min and add the final 4G, I'm acclimating my fish all over again and I haven't lost a fish from a water change.