[pooloss]

Hi Guys,

Our well water is unusable so we've just dropped in a a high-end RO filter. The water is coming out with a TDS of 20 and pH 7.

I have Hesi soft-water nutrients, so in theory they should have everything I need for use with RO water. However, I've read many threads suggesting to add calmag to RO.

Just to be safe, shall I bring my RO water up with calmag to 150 and then add the nutrients?

My concern is adding too much calmag.

Thanks,
PL.

[Douglas.Curtis]

Originally Posted by pooloss

I've read many threads suggesting to add calmag to RO.

Unless your hesi nutes are low in calcium and nitrogen, I'd stick with magnesium sulfate (epsom salt) for the mag differences between strains. Your plants will use both the magnesium and sulfur properly.

15 years running r/o and GH nutes, epsom is all you need when you're mixing the right balance for cannabis.

[pooloss]

Thanks for the reply.

How can I check the Hesi nutes? Just be checking the label?

How much epsom salts would I need?

[Douglas.Curtis]

They should have an online calculator you can mess around with. I use Mel Frank's published numbers as a baseline.

Start with .5g/gallon, I go as high as 1 gram per gallon. I only mix it into the flower res when I start it, none for the rest of the grow, unless still showing mag deficiencies. You should be able to cut fresh flowers, at any time during the flower run, and smoke it without any sparkling from excess magnesium.

[pooloss]

Perfect. Many thanks.

[LostTribe]

check the manufacturers recommendations regarding RO water. With PBP its always 5ml per gallon RO.