[biscuitsawce]

So I have pothos and duckweed growing really fast and draining the water out of my aquarium. Do plants absorb pure water and ammonia only? Or does it absorb water, ammonia, and minerals too? Should I add distilled water to top off my aquarium or remineralized water instead to top off the aquarium?

 

[pauld738]

Minerals too but it's more complicated than that. And don't discount evaporation. Depends on your setup.

Interesting question for sure.

Pothos is good at nitrate uptake as well.

Assuming no water changes (you didn't mention one way or another) and normal fish load with moderate feeding, no co2, low(ish) light, you would want to keep an eye on Gh. Specifically, Ca:Mg. If you are using moderately hard tap water, you have alot of leeway. If you're makeup water is soft then you will need to pay attention to those values.

My gut reaction is to say use distilled water. But it depends on your starting Gh and frequency and volume of water changes. I would be afraid of mineral buildup using moderately hard tap water with extremely infrequent water changes. The reverse is true if your tap is soft and using distilled water for top off.

Sent from my Pixel 3 XL using Tapatalk

 

[ichthyogeek]

I would top off with regular tap water. Yes, the plants are going to take up a lot of minerals and stuff. But most of it is going to be replenished by fish food, and plant fertilizer. Tap water makes up for any micronutrients that end up missing.

Of course, the best way is to just top off with tap, and then do a water change once a week. This helps to reset a lot of changed values.