How much tap water to cut with ro?

[ThatRapperWeed]

Hi all. I've been reading recently about RO water having trouble maintaining ph over time when mixed with nutes due to lack of minerals as a buffer. Since I'm about to be auto feeding, I want to avoid this. Would a good ratio of tap to ro water be 20%? So in my 10 gallon mix I have 2 gallons of tap water that's had the chlorine evaporated off? What do you guys think of this? I also wouldn't mind having more available calcium and magnesium for my coco.

 

[BluePowerRanger]

I use advance nutrients in 50 gallon reses I’ve never had major ph fluctuations.. 100% RO water.. I can go 2 weeks without adjusting my ph and even then it’s only 6.1-6.3 range.. I start at about 5.7 on average..

 

[ThatRapperWeed]

I use advance nutrients in 50 gallon reses I’ve never had major ph fluctuations.. 100% RO water.. I can go 2 weeks without adjusting my ph and even then it’s only 6.1-6.3 range.. I start at about 5.7 on average..

Ok that's what I use. Maybe I won't worry about it as much, hand fed my last grow so I was mixing every day or two depending on how much I had left over.

 

[Pondracer]

Dont worry about it. I use full DI and once I figured out how to mix correctly the swings were greatly reduced. A day or two isnt a big deal at all. My reservoir goes 12-14 days or more, thats when its a headache.

 

[ThatRapperWeed]

Thanks for the responses. What are your thoughts on doing that with the water regardless? My thoughts are if I can reduce how much RO water I use, I make a small savings on my grow from start to finish and I'll have some more naturally available calcium and magnesium. Or is it not a good idea in general?

 

[Pondracer]

Thanks for the responses. What are your thoughts on doing that with the water regardless? My thoughts are if I can reduce how much RO water I use, I make a small savings on my grow from start to finish and I'll have some more naturally available calcium and magnesium. Or is it not a good idea in general?

Sorry for the late reply. I totally think you can, or even just bypass RO all together if you are just using it to lower initial PPM. If there is a problem that you are correcting with RO then that would be different but it doesnt sound like thats why you use it. I did it because I use RO for drinking and I wanted DI for a salt water aquarium. I like having a real flat, consistent baseline when mixing the tank. Honestly the PH swing surprised me because I wasn't getting it when mixing for 3 days supply. When it got out there to 12-14 day (65g) I started to get swings and even within the first 3 days that before seemed fine. Then I started being more careful how I mixed initially and trying to minimize the amount of PH Up or Down that I was using. I really don't know that going to tap water would solve that problem. Practice more than anything probably does the most to minimize that issue. That and the money for a dosing pump :)