Lucas Formula with fresh reservoir suddenly 5.0 not 5.8 anymore

Indoor Growing Hydroponics
#1

I am using lucas formula with tri part from general hydroponics. 0-8-16. I use RO water.

Since half a year i noticed when doing a fresh reservoir that the starting ph is 5.0 not 5.8 anymore.
Before I didn’t need to use a ph up when having a fresh resevoir. The ph was always 5.8.

I checked the ppm and they are perfectly around 1800ppm like always.

I cleaned the reservoir and the tables today thorougly and checked with two ph meters. But still 5.0.

Any idea what can be the issue?

Something with the RO water? Maybe both ph meters damaged?

(A couple of month the name of the product changed from general hydroponics to terra aquatica. But they claim not to have changed the nutrient mix.)

#2

Check the pH of your water before you add anything to it. It’s possible that the pH of your water has changed. What are the PPM’s of your RO water? If it’s higher than 0, you may need to change your membrane and filters.

Also, if using RO, you should add Botanicare Cal-Mag Plus (or something similar). When using it, be sure to add it and mix it in before adding anything else to your reservoir.

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#3

You need harder, more alkaline water to prevent those pH swings.

R/O has no alkalinity. Very subject to pH swings. It is however very easy to add alkalinity to water. Calmag, for example. But for most people, I find it makes more sense to just use tapwater than expend all the time and expense producing pure water and adding minerals back in.

Your meter may also be off and need recalibration.

What are the plants telling you? Are they growing OK?

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#4

lol…I’m not most people. My well water has a pH of around 4.7. I use a chemical injection system to bring that back up to neutral, but that puts way too much potassium in my water. I’ve spent years figuring out what works best for me. I find that, for some people, sometimes it’s easier to start with a blank canvas when having water issues, and RO water is a blank canvas.

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#5

4.7?! What’s in god’s name is in your well water? Iron mine runoff lol? Any wells I’ve ever seen definitely trended far more towards alkaline than acid…but I’m in the Midwest and the USA is a biiig country.

I hear you, it’s easy to start with a blank canvas. I had a unit for my aquariums, but the critters and plants I kept were far more sensitive than weed.

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#6

also check and re-calibrate you meter if you haven’t.

#7

Haha…yeah, it’s bad! I’m in the mountains, and I’m on a plateau, so runoff isn’t the issue. The good news is that my water is pure. It’s been tested by a state lab and has zero PPM’s (before treatment).

We moved here after living in the suburbs, where we had municipal water. Back then, I grew in soil and used my tap water to get outstanding results; far superior to what I’m getting now. Believe me, if I could use city water, I’d scrap the RO in an instant!!

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#8

Wow 1800. Hmmmm.

These ppm numbers are based on the 500 scale.

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Make sure it’s not the hard water Micro formula.

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#9

That’s nuts. I’ve always known there was acidic groundwater like those springs in Yellowstone that dissolve the bodies when people fall in (happens EVERY year those signs are for a reason lol) I just haven’t known anyone with anything but alkaline wells.

My wife sometimes talks about living in the country and how cheap it is and I’m like yeah the house is cheap now factor in the well, septic, generators…etc…I remember my grandma needed a new well pump and she said it was 20K for the job in 2005 money. WTF.

I need to not take municipal tapwater for granted haha.

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#10

Very hard water is way more difficult to deal with than RO.

If you have always used RO water, then I am not certain what the issue is. Like @GramTorino 1800ppm is a very high number. Your RO water will be like <25ppm, unless it has a remineralizer. That will do nothing to the pH compared to the huge amount of nutrient.

Bottom line is that when you use RO water, the pH of the nutrients as mixed will be the only thing that matters. So that means they might have changed their formula (like using more MKP and less DKP). However if you were using RO + remineralizer, then maybe it’s possible that the remineralizer has depleted. Or, maybe it’s time to replace the filters on your RO system.

Check the ppms of your RO water. If they are not very low (like <25ppm), then it is an issue. If your RO system is working and you have low ppms, it’s very unlikely that your water is the problem.

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#11

Have you thought about trying the auto ph nute lines? I never had the best results with GH but I never gave it my all either so…? I hope you can figure this out bud!

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#12

hmmm… why is it high? I am doing 8/16 Lucas. So I guess we use a different scale?

#13

what is the exact name of the brand/product? Can you do a Lucas formula thing with it?

#14

ro water seems right. no mineralizer stuff.

I am not using the hardwater version of the nutes.

I wondered if it can be a residue of something in the irrigation system.