Nute buildup/res change/top off

[Bluebuddha]

I'm currently running 90 gallons in RDWC, PPM's have been maintained between 500-600 using Jack's 321, Cal/mag .25% strength, Mr fulvic, TPS billions and Orca. I'm at the 3rd res top off where I've added 30 gallons of PHd at 5.8, 525 ppm. I've now topped off the entire 90 gallons.

3 strains in the system.

Grape Cream Cake
MB15
88G13HP

I'm noticing some lightening of the fan leaves in the 88G13HP. (week 3 of 12/12) All other plants look perfect.

Is salt buildup in a res a myth? I've read that calcium is a slow mover so it could buildup after a while with no changes. This last top off I left out the CalMag and just used Jacks A and B. I also top dressed with Cal Nitrate to hopefully get a jump on a N deficiency.

I really don't want to change out a full 90 gallons as it will take a couple days.

I would think you wouldn't have to change out a larger res so often and it's only been 2.5 months.

Anyone have thoughts?

 

[SweetLeafGrow]

I'm no expert bro so check with others before you take my advice but....

I know @Aqua Man recommends changing out your res after you have topped off the total amount in your system. I know others say they can go the distance without a change. I think @Moe.Red has said he is going to do just that in an upcoming grow, I am curious to see how that goes.

My current style is to avoid changing the res out. If it aint broke.....right? With that said, I do want to change when I make the transition to flower so I get my flowering ratios where they need to be for that stage of growth, or if a problem arises and I need to reset everything. I am sure there is a way to amend from veg to flower, I just don't know how to do that to get the ratios where they need to be, which I do believe is important if you want to avoid deficiencies.

I could be wrong, but it looks hungry to me with the yellowing on the lower fans. I've never used Jacks but to me, the ppm's seem to be a bit low but if the others are fine, perhaps it's that this one plant is a heavier feeder than the others. The way I understand it, this is an issue when you run different strains, with different needs in the same system.

Lets see what the experts say!

 

[Bluebuddha]

I guess I'll give it a couple days to see if the added N foliar and added CalNit in res helps. Running the diff strains is a pain in the ass. I also let the first back go to long in veg so now they're max'd out on height