wow 700ppm tap water is very hard water,............... same as i have here, and is why i went onto RO, as high calcium carbonate levels in tap water, over the 300ltrs fed, over the 80-100 days, can block the substrate up with un used salts, which can alter the Ph near the end of the grow.............
This is hopw i use my RO, i buffer it with my hard tap water, (Add Back Calcium carbonate Salt), but to a lesser degree............ buffering RO with calcium carbonate, at 250ppm, allows Ph to stabalize when making up nutrients, in addition, calcium is needed in sensibble levels, for normal somatic growth auto ok...........
i recommend you buffer your pre aerated RO @23c, to "250ppm"................... or Ec0.25, it also stabalizes your nutes when in solution............ another boon, is you dont have to use much "Ph Down" at all,..................in fact if you get the alkaline salt buffer right, after you add your acidic nutes, your Ph can be "6.5" and no Ph down needed......
run off allows monitoring, but never leave the plant sitting in stale run off, ever......... you can raise the pot on 40mm supports, the plant cant sit in water.......... from mid flower, to the end of flower drinking will slowly drop of to half or less of normal.......... leaving a plant sitting in water, leads to anerobic bacterial conditions, worse, it produces H202 'Hydrogen sulphide"......................super toxic to roots at 0.1mg/Ltr = avoid it, if you ever get the smell of rotton egg's just after a watering, that the water going in pushing out the hydrogen sulphide........... in those cuircumstances,...................let the plant soil dry right out over 2 days 48hrs lights on...............then flush with highly oxygenated aerated pure RO.................
cocco cultivate + perlite product, has no pre nute in it. so the run off at 750ppm when you are feeding 350ppm Qs is that on the "Hanna" scale ??........... as 350ppm is Ec0.7....................that is a good strength nute for feeding, not to strong, just on the bliss point........ your tap water is Ec 1.5 twice the salt you are feeding in total,...................you see how tap water can build up salt and ruin a substrate Ph !!
View attachment 1067456
here is the reason your run off ppm is 750 and your nute "Going In" is 350ppm, i a word, 'Floraclean" this is designed to break down mineral salts in the substrate used,..................in your case cocco is almost 50% calcium based mineral product.....................calcium bound up in cocco fibre is alkaline, so as the floraclean goes in, it is dissolving the alkaline calcium inherent in the coocco fiber....... the floraclean is stripping out the calcium in the cocco........... and raising the ppm of the run off,....up to 750 and will climb further, the more you use the mineral stripper !!................the more floraclean you use the more calcium will be washed out, "Chemically liberated" from the cocco................. for that reason, i dont recommend using a hydroponic cleaner in cocco auto............as later on in the grow, it will lead to Ph issues.......best to all........... ALR
Addendum;
for every Ltrs of RO coming out of the membrane at 3bar, 3.5 to 4.5 Ltrs of tap water is bypassed through the filter system,.......................so every litre produced, 1 litre every 30 minutes.......... up to 4.5 liters of water, 75% are wasted via the 6mm red bypass pipe............. to the waste outlet.......... around 2 bath volume per week, to push up your water bill............. for this reason, if you can, use "Rainwater" run though a 50 micron sack filter, such as a Rosin press, rosin filter bag 80mm x 100mm..............
Accordingly, to filter out black-fly, white-fly, mozi larvae, and debris from water butt................. aerate it, and raise temp to 23c................ mix the RO with tap water no problems, just buffer it the same to 250ppm with "Raw" tap water....... ALR
