Quite a diff. The claim shell or whatever they use for buffering (they say) will through off runoff readings. So I will have to get some distilled next trip to the store. In the mean time I just flush and prey! LOL kinda. Looks like we have the same meter.
Yeah, the oyster shell is supposed to be the buffer. As for it throwing off the runoff, Iâm not so sure. I never run across issues in veg when the runoff is 6.5-6.8. Itâs when I get into late flower and runoff is 6.1 that I start seeing magnesium deficiencies
Well sheâs still growing a bit so flush, if she improves flip and move on. If not dig up and start over.
One thing to consider is which scale are you using when talking about ppm? 500, 700 or ec. All have a diff value. If you say for example 500pm and your scale uses 500 scale and somebody replies and tells you to do this and this and they are using 700 scale it could cause more problems
I have always been told when doing a slurry with tap water to check ppm b4 adding to soil. Then when you do slurry subtract tap water ppm from slurry ppm to get ppm of soil. So for example my last slurry was as follows:
Tap water ph 6.9 ppm(700) was 190 @69 degrees.
Slurry ph was 6.3 and ppm(700) was 680
Subtract 680-190= 490. Right at the lowest threshold. And ph was a bit low so I increased ph to 6.7 and added a little more nutes
You wonât get a proper soil ph that way due to the tap water buffering the ph. Distilled and RO water will take on the ph of whatever itâs added to. Tap water will change the ph of whatever itâs added to.
If youâre doing a slurry for ppm with tap water, youâre just adding a step by having to subtract the starting ppm from the total. If you start with 0 ppm water, no need to subtract anything.
The TDs readings arenât the problem as I see it, itâs the ph thatâs dropping (according to runoff readings) to low readings. The ph dropped by a full point from 6.8 in to 5.8 out. Thatâs a factor 10 times the input readings.
Thatâs why you ph it to 7.0 (+/- .2). I havenât had to ph my tap water to 7.0 because it normally test at 6.9-7.1 which is with in the limit
Iâm confused. Are you talking about an actual slurry test or runoff test?
Slurry test
Then adding tap water to your soil is going to change your test soils ph. Which eliminates what youâre trying to do. The pics I posted above show the difference. When soil is added to distilled or RO water you get your actual soils ph (5.4 in the case of my test). When you add phâd tap water you get an adjusted soil ph (6.3 with tap phâd to 6.5).
Yeah, thatâs a little misleading when they say âph neutralâ. They should have added âpure waterâ. Tap isnât pure. It has solids in it that hold its ph. Pure water will adjust to the mediumâs ph thatâs added to it. Tap will adjust the medium itself.
Good morn all. Just finished a 5gal flush with ph ed tap. In at 6.8 out 6.1. TDs in 300. TDs out 469. Sooooo I guess u let it dry out (couple of days I imagine). Than start full dose neut feeds???
Yep, sheâs gonna need those nutes. May want to add a gallon of 1/2 strength feed now while sheâs still wet. Could be 5 days or so for her to dry out from the flush.
Hell sheâs treading water and holding her breath as it is! LOL. Will it even stay in the soil?? The last 2 1/2 gallons of flush seemed to just flow right out as fast as I put it in.
Ok itâs been 2 days since flush. Should be ready for a feed? FF says do a full neut mix according to the FF chart. Would like some feedback on this please. @BobbyDigital. Iâve always reduced the recommended amounts in past grows but with this issue just not confident. The soil should be almost devoid of nutrients after flush (tds reading in the 400+ range).
When I flush, the last gallon is always the feed. Youâre going to want to let her dry out completely or you could end up with wet feet issues.
Iâll let it go another day and ck the soil, it is still a little damp an inch or two below the top. At what ph would you recommend for this feed when soil drys? And at what strength??? Iâm figuring using the 4th week feed.
I would be phâing to 6.8-7.0 for the rest of the grow. For feed, you can always go full strength with the big bloom. I would go 1/2 strength with the grow big and see where your ppms are at. Iâd shoot for 800-1000ppm for the first liquid nute feed. If you have boomerang, Iâd go 1/2 strength with that too. If your solution ppm is below 800 after adding those nutes, you can add some more grow big or boomerang to bring the ppm up.