We are talking about adding cal mag to plain low ppm (50ppm) water so it can be adjusted appropriately in pH to combat low medium pH. Feed regiment has not yet started
@Bfreezy
There are a lot of successful growers using flora just hit that search bar.
@kaptain3d
Maybe will know of some directly to minimize search.
This is the one people use “Lucas formula” for??
@Mntmannw ??
Thanks for the tag. I am no help.
Sorry…maybe @MeEasy then? 
Not sure I can help much, the Lucas formula was adjusted from the GH 3 part feed schedule. It was determined that the “grow” wasn’t needed, just micro and bloom. Since using the Lucas formula I have not had to add cal mag or any other additive except for bloom enhancers towards the end.
I’m not a well educated person when it comes to nutrients I just follow the suggested dosage. I have had very good luck with the Lucas formula and kool bloom towards the end.
If I missed the point please let me know.
By the way, I’m on well water
Thanks for the tag @kaptain3d But I’m afraid I’m not gonna be much help either. I used Fox Farm trio for a few years but it’s been at least 5 years ago.
I can say that the recommended flushing by Fox is not the same as a total flush you would do to reset your PH. It’s done using Sledgehammer and only until you get a decent runoff. It’s pretty much just to keep the salts from building up. I liked how it worked and still use the Sledgehammer in my living soil all it is is yucca extract and more of a soil conditioner
Anyone have advice on this line for OP?
@Mark0427 might have used those I’m fairly sure…
Thanks @kaptain3d for your efforts I just don’t want the OP ditching the nutrients they already have on hand. I know I’ve heard them used effectively. Maybe even @dbrn32 would know
@Mntmannw
How would you advise OP for using the GH flora trio? I’d assume they are relatively new and looking for a place to start with them. Seems to be getting conflicting info from searches and bottle recommendations.
I have not used the flora trio, only the GH original, Flora is a different line. I’m also in hydro, so that would be different also.
On another note GH has a new line out now(I believe it’s GH) called strive.
Ok, sorry for my misinterpretation just trying to help. Appreciate your time either way.
No problem wish I could help more.
The gh stuff will work.
What I read here is that op tested runoff from happy frog that is fresh as of couple days ago when it was transplant from solo cup. Nothing surprising here, its a fresh bag of amended soil. As pointed out, even when this is high it’s not all plant available as it will require being broken down by microbial life before plants can process. So the fact that it’s high just means it should be good for a while with healthy watering practices.
Also not surprised the ph is a little low, it is fox farms after all. This can be fixed by working a few tablespoons worth of fine dolomite lime into the top couple inches of soil.
It’s correct that very low ppm water won’t test properly on most of our tools. Not to be alarmed, stripped water will usually just take the ph of whatever is added to. So as long as your soil is buffering close and isn’t stripped of ammendments i wouldn’t even bother setting ph of water that’s at or below 50 maybe even 100ppm. But if you need to, then getting water to ~150ppm is usually plenty to test ph accurately.
Hope this helps!
I used fox farm happy frog and ocean forest soil and fox farm Trio for nutrients before I went to coco. Me personally I never look at runoff numbers until something is wrong. That’s just me. Your plant looks fine I wouldn’t sweat a thing now. I’ve caused myself more problems by chasing ph and ppms. I pretty much feed as heavy as the plants will let me. When you see a tad of tip burn back off a tad on the nutes. And I’ve gotten to 2500ppm in late veg before and the plant still wanted more. Some plants can take as much as you give them some are picky on ph and ppms. I’m fortunate 6 of my 8 different strains are diggin the very heavy feed schedule 2 ain’t. And the ph on the ones thriving in the trays is 6.5 to 6.8 im goin in at 5.8 and I’m in coco so that’s way high coming out. But the plants ain’t complaining one bit. Well 2 are and 6 ain’t 
I think the only one that’s marked OMRI is there BIg Bloom. Don’t quote me on that
Just saw the tag , thank you @Low . I use GH in hydro and soiless media. I have used Lucas Formula in hydro. Is there a question ?
My water tests at 100-110ppms. The Ph hovers around 7.6 but it takes forever for the meter to stop going up or down. I add silica or cal mag to get a stable ph. If I add 2-3ml of silica or cal mag it reads 8.0-8.4. After that I add nutes to 2.0 ec. The ph ends up around 5.9-6.1
Edit I know nothing about the nutes the Op is planning on using. I use
Rainbow mix and Jack’s 321 no need to flush using these.
Sounds like we are on the same well @plumbdand … the numbers are the same. When I am using GH in soiless mixture (promix premium moisture and 1/3 perlite) I PH to 6.2. Seldom check run-off. On the first watering the runoff ph’d at 6.4 so the next watering I adjusted to 6.3 ph and let it roll.
I don’t think so. I think low just tagged you for general advice on this line of nutes. I’ve heard of the Lucas formula, heard mostly good things
Hey @Bfreezy . I’m late to the discussion but wanted to offer my experience. I use FFHF as well, but I did amend the soil with 3 tablespoons of roadside organics veg per 7 gallon container. First month or so I used strictly RO and I had high EC numbers not unlike what you are seeing. However, my runoff Ph was on point (6.3-6.5). I haven’t had any real problems with the plants - actually they stormed thru veg and after the flip with crazy growth. YMMV, but I bet they will be fine.