Ro/di

I have a fowlr set up and I started off with conditioned tap water. Its ben going for about 3 weeks and it seems fine. I will buy the RO/DI unit if i need to but is it really something that i absolutely need to have?

 

It not only is a great source for ultra clean water, but it acts as a great evaporation top off when used with a float valve in the return section of your sump.

RODI is super clean water and is very healthy for your fish, it also helps prevent diatom algae break outs.

 

sorry, but what is the difference between RO/DI and distilled?( end product, not process ) why do so many people recommened ro/di over distilled

 

Conditioned tap water may be OK, depending on the exact makeup of the water. Some people use it for years and have no problems, others switch to RO/DI and find it's a lifesaver and their tanks look a hundred times better after switching.

With RO/DI it's consistent and a known quantity. Using tap water your water is probably going to vary over the course of the year and could change at a moment's notice if your city decides to change their processing, or maybe a farmer up the road changes fertilizers or any number of things can happen to affect your water supply.
I would hate to have to try and troubleshoot water quality problems if all of a sudden things start dying in the tank and you have no idea why, the water supply could always be a source of problems.

Tap water will probably be adding nutrients to your tank (nitrates/phosphates) which can fuel algae/bacterial outbreaks etc. Not necessarily a bad thing but it can be a struggle to keep water parameters good enough without having inherent nutrients in your water from the start.

Also, if you have any copper plumbing in the house, or anywhere along the line you probably won't be able to use that if you want to keep any inverts.

3 weeks is not really long enough to be a good indicator of the long-term effects of using your tap water. It could take a while before you start seeing the effects of excess nutrients etc.

I would just bite the bullet and get the RO/DI unit personally, take that out of the equation. Your water is pretty much the most important thing for keeping things alive, I wouldn't skimp on it.

Also, one thing about distilled vs RO/DI. I don't know of many people that want to run a still in their house. Maybe there's a super efficient compact one I'm not aware of though.
Distilled is a valid substitute for RODI water AFAIK though.