Is tap water bad for plants?

When I first set up my planted discus tank I used 100% R/O water (with added Kent Marine "R/O Right"). My plants grew extremely well, so well in fact that I often had to prune them to allow swimming space for the discus. A couple of months ago I read in the beginners' section here at "Simply Discus" that it is okay to use part tap water and part R/O water. This allowed me to increase the quantity and frequency of my water changes (since my tap water is free) and I am sure that that has increased the well being of my discus...

...but my plants seemed to really have suffered. I do not have the rampant and luxurious grouth that I did before. My water sprite and hygrophilia have almost withered away completely!

Has anyone experienced anything like this? Could there be something in municipal tap water that is harmful to plants? ??? Is there something else that may have changed that I have not considered?

Tyra

Hi!

Not likely a polutant issue, I would have to say something to do with not having enough dissolved carbon dioxide in tap?

I would look towards a more experienced plant keeper but I woul dhave to say that it could be a number of things that have lead to the downfall of you poor plants.

Sorry I am not of much help...

Chong

i believe plants dont like regular wc. if you look into amano's book, he did wc every 2weeks or so. wc good for discus on the other hand bad for your plant unless you keep dosing supplements needed for your plants to your tank regularly.

It has been a long time since I've added CO2 to this tank. I stopped because I was worried that the occasional fluctuations in pH were harmful to the discus. I might try a small DIY CO2 setup and then try to watch the pH more closely.

Tyra

Tyra,

I do 50% weekly WC with straight tap water in my tanks. I have no problems at all with plant growth in any of my tanks as long as I keep up with my fertilizers and CO2. If I don't, it doesn't matter what kind of water I use, they die.

I think your issue lies in Biogenic Decalcification. That is, when you added the "RO Right" you were adding carbonate to the water that your plants used in place of CO2. Most plants can do this to some extent or another but it's not easy and they don't prefer it. When you cut down on the chemicals your plants didn't get enough carbon and started dying.

Note: I add SeaChem's "Equilibrium" or plain old Baking Soda (Sodium Bicarbonate) to my aquarium to get the KH and GH up to around 4* (my tap's not really measurable). What that does is create enough buffer that I'm able to avoid massive pH swings. Equilibrium is good if your plants start showing signs of Calcium deficiency....Baking Soda's a lot cheaper. :)

In many cases, tap water is fine for plants. I use 100% tap water and I use CO2. I change about 50% each week.

Perhaps your tap water doesn't have all the minerals, trace elements, etc.. that you added into your straight R/O water via R/O Right? I'm assuming you've cut back on the amount of R/O right you're using since you're mixing tap with R/O water.

What are the parameters for your tap water? Maybe you can add a little more R/O Right?

HTH,

Walter

I think it depends on where you live. I usually use an RO unit for water changes. I decided to get to try doing water changes with tap water. Next thing I knew, I was having an algae out break. With my high light I usually get a lot of green spot and some black spot, but this time I was getting filamentious and black brush. I stopped teh tap and switched back to RO and after a month the algae was gone.

ONe trick if you are using straight RO - like I continue to do - is putting a small back of coral in your filter. For my 120 gallon, I use about a fist full of coral. This addition as been great at keeping the KH at a level that I prefer.