I’m a fairly new grower (on my 4th grow) and am considering installing a reverse osmosis water filter in my grow room, but am not sure it really will make a difference. I’m a hobbyist growing for fun and have improved my technique greatly since my 1st grow. I don’t need super high yields and am more interested in quality over quantity.
My current grow - 2 photoperiod plants: 1 Gorilla Glue x Zkittlez and 1 OG Kush - are doing pretty well. They are in week 6 of flower and seem to be healthy and are getting nice bud growth (see pics below).
They’re grown in 5 gallon fabric pots filled with FoxFarm HappyFrog soil (70%) mixed with perlite (20%) and vermiculite (10%). I’m on an every other day watering schedule and I feed them Jack’s 321 nutrients. I adjust the input pH to 5.7-5.8, and my runoff pH is 6.2-6.3.
I’ve struggled figuring out the right strength/frequency to feed at to keep EC down. For this grow, I’ve settled on mixing the Jacks 321 nutes at 1/2 the recommended strength and feeding about once every 6 days. Then when my runoff EC gets in the high 2’s (2.7 and up), I’ll do a flush with pH balanced tap water until I get EC down below 2. I end up doing a flush about every 2 weeks.
I live in an area with pretty hard water. EC for my tap water is 1.2.
So my thinking was … if I can lower the EC of my tap water with an RO system, I should be able to mix my 321 nutes at higher strength and/or feed more often, while keeping runoff EC down, in the 2 - 2.4 range that’s recommended on the Jacks 321 nutrition schedule.
Does that make sense? Will I be able to feed more nutrients to my plants if I filter out most of the dissolved solids in my tap water with an RO filter?
I’m also going to be changing growing medium on future grows. I’ll probably try ProMix HP (peat based) next, then maybe Coco coir, and finally maybe try a DWC setup. Is an RO filter more/less of a need for soilless grows like those?
I would strongly consider an RO system. The under sink units are pretty affordable (~$200). That way you can run more fertilizer but you can also still mix in some tap water for the micro nutrients/minerals your feed might not supplement. As a bonus if your tap water tastes like dirt like mine does r/o is much more pleasant to drink or make ice out of.
I would probably buy distilled water $1.29 at Walmart since you only have a few weeks left before harvest. Then I’d get an RO before my next growl 1.2ec is pretty high that’s around 600 ppms I would try to find out whats in your water. I definitely wouldn’t drink it, cook with it or make ice without knowing whats in it. You shouldn’t need to be flushing evry 2 weeks. Specially when using Jacks
With tap EC at 1.2, you’re already starting “halfway full,” so yeah—your idea is right: RO (near 0 EC) gives you full control over what goes in. That means cleaner feeding, less salt buildup, fewer flushes, and more consistent results.
thanks for all the great feedback! You’ve convinced me to install an RO system. It’ll be nice to know what is going into my plants.
I’m assuming the 600 ppms in my base tap water isn’t necessarily harmful, since the plants are doing well, but I have to assume swapping out those for actual nutrients the plants can use will improve growth.
I’m kind of in the same boat @chester - my plumber gave me two options - a $500 one and a $1500 one… I still have to look up the differences and if forking out an extra grand could possibly be worth it
I just bought a RO system at a auction Brand new $33..
It’s $225 on eBay so probably $350 retail just got to keep an eye out on the local auction if you have and close to you.
Or even check any kind of liquidator stores .
Never know what you can find..
UPDATE: I end up buying and installing a waterdrop G5P700A filter for about $300 - very easy installation. It dropped my ppms from 600 (tap water) to 21 after running through the RO filter. I’m looking forward to mixing my nutes at higher strength and hopefully keeping my EC down.
