View Full Version : Thoughts on water sources for Macro Tanks

07/18/2017, 10:03 AM
Wondered what everyones thought on water sources for their macro tanks?

for example
- super pure from home RODI or Fish store
- well filtered but not as "Pure" water from the water vending machines
- tap water de-chlorinated

Other than one water change with clean as possible water to combat dino's I have been using the 2nd option as I think it may be benefiting the macros with slightly "Dirty" water

07/18/2017, 10:38 AM
I use tap. ammonia <0.02, nitrite <0.10, nitrate 0.07, phosphorous <0.01, TDS 73, magnesium 2.1, Alk 37.0, Ca 41.7 (all ppm)
As far as the comparison to option 2 (well filtered water such as bottled water), my tap has: higher Ca, Alk, Magnesium; lower nitrate; equivalent nitrite, ammonia, phosphorous and TDS.
So it's no RODI but there's little difference between filtered and tap water for me. Also costs about $0.02 per gallon :)

07/19/2017, 06:24 AM
I have a friend who uses the Water Change water from her Reef Tank as the source water for her Macro tank.

Michael Hoaster
07/19/2017, 12:31 PM
I have RO/DI for auto top off, but I doubt it is necessary for planted tanks. Just about any water should be fine, as long as it doesn't have a bunch of phosphate or copper.

07/19/2017, 01:52 PM
I would agree on the copper but wouldn't you think the phosphates would be a good food source for the macro's?

Michael Hoaster
07/19/2017, 02:58 PM
Absolutely, BonesCJ, in theory. But practically, we already have a great source of phosphates with fish food. So if you used phosphate heavy water AND feed your fish, you would very likely end up with too much phosphate, and trigger unwanted micro algae. The Carbon-Nitrogen-Phosphate ratio for macros is in the neighborhood of 300-30-1. With phosphate being 1, it is very easy to end up with way too much, just by feeding, even with pure water.

If you were going fishless, phosphate heavy water would be helpful.

This is one instance where planted tanks and reefs have something in common. We both need to keep phosphates low. Even phosphate absorbing media can be helpful in a planted tank, if it is fed heavily.

If we can approach that ideal C-N-P ratio in our planted tanks, we're all good!

07/20/2017, 06:10 PM
Ahhh good point, wasn't aware of the ratio