Help What is best for the freshwater planted tank... RO/DI or just RO?

[Joel Armstrong]

I plan to switch from tap water to remineralising my own and I'd like to seek some assistance before purchasing a system.

What is best for the freshwater planted tank? RO/DI or just RO?

At a guess I would have thought RO/DI, but I'm not 100% sure.

Thank you

 

[Joel Armstrong]

Here is what I did on my RO storage tank.

There’s a submersible pump inside that feeds up to the vertical PVC pipe on the left of the photo. I split the return line in two and added valves to each. The pipe that goes back to the center of the storage tank has a 45 degree elbow on it, so the water pushes into a sort of whirlpool inside the tank. This pushes anything that might settle back to the center, where it’s picked up by the pump and pushed through again. When it’s time to change the water, I reverse the valves. The vertical portion after the T-union is corrected to a hose, then to a “hook” that hangs on the side of the tank.

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Thank you

It's helpful to see how others set up their systems.

Appreciated

 

[Immortal1]

Thank you

It's helpful to see how others set up their systems.

Appreciated

If you look at post #18 of my Build thread you can see my crazy / cramped RO setup. Does the job for me rather nicely.

 

[Joel Armstrong]

If you look at post #18 of my Build thread you can see my crazy / cramped RO setup. Does the job for me rather nicely.

I'll check it out, cheers

Thank you

 

[Joel Armstrong]

I still haven't had the time to set up my RO system yet. I plan to over Christmas break.

Another newbie question..

For you guys using RO, do you just pump the RO water straight to your aquarium, and then dry dose the Ca and Mg etc directly to your aquarium OR do you remineralise your RO in your storage drums before pumping the water to your aquarium? Does it really matter?

 

[FrankZ]

dry dose the Ca and Mg etc directly to your aquarium

This is exactly what I do but I use my RODI for other uses that require it to be 0 everything. I don’t think either way makes much of a difference beyond visual cloudiness and residual gypsum laying in the tank for half a day by dosing directly to the aquarium.

 

[Unexpected]

I use Brute grey trash cans so I know the exact volume. I dose everything in the cans so I don’t have to worry about water change amounts. A little more or less is no problem.

 

[Art]

I use Brute grey trash cans so I know the exact volume. I dose everything in the cans so I don’t have to worry about water change amounts. A little more or less is no problem.

This is what I used to do as well. I liked the peace of mind that I could control everything before going into the aquarium.

 

[Joel Armstrong]

This is what I used to do as well. I liked the peace of mind that I could control everything before going into the aquarium.

Is measuring the amount of water removed from aquarium when performing a water change, and then dry dosing the aquarium based on new water added going to be any different?

 

[Unexpected]

Is measuring the amount of water removed from aquarium when performing a water change, and then dry dosing the aquarium based on new water added going to be any different?

Same thing really.

 

[Art]

Joel,

The dosing concept should be the same as @Unexpected said. My question is whether you are dosing based just on your water change percentage or total water column?

My objective is to try and maintain a consistent nutrient level in the aquarium. So, I've calculated an assumed uptake rate for my current tank. Then I calculate what a 50% water change will do (i.e., how much of the nutrient base is removed). This is my base nutrient level.

I then calculate how much do I need to dose to bring the base nutrient level back up to the consistent nutrient level I want in the tank. To do this, I measure using the total water column value. This requires a front load of nutrients right after the water change.

Did I explain that correctly? How are you doing it?

 

[Joel Armstrong]

Did I explain that correctly? How are you doing it?

Hi Art,

Yeah, you explained it fine, cheers.

I'm dosing (front loading) based on water change amount. I target dose the new water added to aquarium.

I am not accounting for assumed uptake rate of plants though, although I'm interested in doing so. How do you make this "assumption" of plant uptake? I wouldn't have thought hobbyists tests are accurate enough, unless this is done over time perhaps, dunno. I do have some salifert freshwater test kits, but to be honest, decifering shades of colours, i find a bit annoying
I could use a little help with this. Are there testing devices available that will give accurate numbers, instead of colours?

I'm using tap, still haven't set up the RO system.

More than happy to take on your advice

 

[Art]

Joel,

I can share with you how I do it. There absolutely may be better ways to do this, however. I'm hoping someone else chimes in.

I too am not a fan of guessing colors with test kits so I opt for the Hanna Colorimeters when I can. Unfortunately, they don't have one for freshwater nitrate.

The method I use:
Anyway, the point is to take a reading at a beginning point and then a reading at the ending point. I usually do this right after a large water change and dosing. This is my beginning point. Do not fertilize for the week. I then take a test right before doing the weekly water change. This is my ending point. The difference between the beginning point and ending point, all other things assumed, is your plant uptake for the time period.

I do the above (very occasionally) with the big nutrients such as nitrate, phosphate, potassium. I also guesstimate the micros by tracking iron.

In the end, what I'm looking for is a trend more than a specific number. I do want to see a downward trend for the week indicating some uptake. However, I do take the test kit confirmed uptake amount and use it to educate how much I will front load nutrients in my next weekly cycle.

How important is this:
Well, if you have good husbandry practices and (IMO) do the occasional larger water change, I don't think knowing a rough estimate of your plants' uptake is that valuable. Over time, you likely will not get to any nutrient level that throws things off.

If you do want to do lean dosing or, if you follow @Dennis Wong and his low nitrate dosing, I guess knowing uptake amount may be able to help you walk the tightrope in your dosing regime.

For me, the above has been helpful on occasion. For example, one time I did see that my plant uptake was significantly different than a couple of months before. I hadn't changed anything nor heavily trimmed the plants. It sent me on a search to see why the plants were taking up less nutrients. Turns out my auto-doser needed calibration. This is when I learned that an auto-doser needs to be calibrated every so often.

 

[*Ci*]

In this koi forum thread, we had a hack going to use a Hanna Chlorine Colorimeter to measure Nitrate. It’s been awhile since I used it, but it did work well, though it takes a bit of experimenting to get it set up correctly.

Nitrate Level hack using Hanna Chlorine ULR meter and API Mater Test kit

 

[Joel Armstrong]

Joel,

I can share with you how I do it. There absolutely may be better ways to do this, however. I'm hoping someone else chimes in.

I too am not a fan of guessing colors with test kits so I opt for the Hanna Colorimeters when I can. Unfortunately, they don't have one for freshwater nitrate.

The method I use:
Anyway, the point is to take a reading at a beginning point and then a reading at the ending point. I usually do this right after a large water change and dosing. This is my beginning point. Do not fertilize for the week. I then take a test right before doing the weekly water change. This is my ending point. The difference between the beginning point and ending point, all other things assumed, is your plant uptake for the time period.

I do the above (very occasionally) with the big nutrients such as nitrate, phosphate, potassium. I also guesstimate the micros by tracking iron.

In the end, what I'm looking for is a trend more than a specific number. I do want to see a downward trend for the week indicating some uptake. However, I do take the test kit confirmed uptake amount and use it to educate how much I will front load nutrients in my next weekly cycle.

How important is this:
Well, if you have good husbandry practices and (IMO) do the occasional larger water change, I don't think knowing a rough estimate of your plants' uptake is that valuable. Over time, you likely will not get to any nutrient level that throws things off.

If you do want to do lean dosing or, if you follow @Dennis Wong and his low nitrate dosing, I guess knowing uptake amount may be able to help you walk the tightrope in your dosing regime.

For me, the above has been helpful on occasion. For example, one time I did see that my plant uptake was significantly different than a couple of months before. I hadn't changed anything nor heavily trimmed the plants. It sent me on a search to see why the plants were taking up less nutrients. Turns out my auto-doser needed calibration. This is when I learned that an auto-doser needs to be calibrated every so often.

Thank you Art, I appreciate your detailed explanation.

What are you using to test for Nitrate?
Potassium is not available in a Hanna colorimeter either if I'm correct.
Am I right in assuming that you have a Hanna colorimeter for Phosphate and Iron only?

 

[Art]

I have Hanna for phosphate, iron and alkalinity. I'm using Salifert for the others.

The two things I try to keep in mind when thinking about testing are:

1. Test kits are not very accurate. I tell myself to just look for macro trends.
2. Test kits need to be calibrated and they do expire (check the date!).

My MO is to test often after setting up the aquarium. As I begin to get a feel for how it's running, I back off to once a month or so. Probably more towards the "or so".