PH dropping Too low. Every nite

The PH in my 5 Gal DWC bucket drops every night sometimes every 12 hours to around 5.0
I adjust it by drawing off 1 liter and replacing it with fresh 7.0 water about PPM 600, EC about 1300 and sometimes silica PH+
But next day = 4.9- 5.0. I’ve stopped adding any Cal-mag about a week ago. The roots look pretty clean and white. In fact it’s the best looking healthiest plant I have.
The other three are in Rockwool.
The light is the spider farmer SF-2000 at about 75% 20” up.

Date. PH Low/Hi. PPM. EC. TEMP. F
8/16. 5.0/5.6 623. 1307. 74.8
8/18. 4.8/5.8. 683 1253. 76.3
8/19. 5.4/5.7. 660. 1320. 75.7
8/21. 5.0/6.2. 720. 1441. 74.5

One other thing I have started cutting the big fan leaves off probably about 5-6 a week And went to 12/12 flowering 2 days ago.


I don’t do hydro, but I was still intrigued by a Facebook ad today for a product called PerfectpH from
Torus Hydro. It’s a device you fill with adjusting solution and place it in your reservoir and it keeps pH in the required range. Depending on size of unit they say you can go 2-4 months between refilling. No idea what they cost, only looked at it from interest standpoint.

Anyone here try this? Does it do what it says It does? I sure like gadgets.


I read about it also. But not by anyone here, I’d rather not be the first.

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I have exactly the same issue in DWC.

So at 8AM, I pH’ed the plant back up to 6.1 (from an overnight drop to 4.5)

Now 9 hours later, I checked again, pH dropped to 5.1

During this period, nutrients dropped slightly from 390ppm to 360ppm. Water only dropped around 100mL.

Any ideas whats going on?!

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In a hydroponic (water) grow, the only way to achieve a balance ph is by having a large volume of water. (Pending on dif. circumstances)
As the plant grows, in a 5 gal bucket, there’s just not enough water to balance out the transformation of everything that’s going on within your water/nutes/plants. A good size plant will fill that five gal bucket easy.

That’s why a lot of folks go with RDWC instead. Or at least adding some type of reservoir.

I’ve heard a few good things about the PH Perfect and may try it if I keep seeing good things.

I have 20 gal in my system and the only time I had problem is during the stretch when they were drinking 2 1/2 gal a day.

Five gal buckets will grow but you will have trouble with ph throughout your grow.

I’m week 6 of flower and now it’s pretty much set it and forget it, at least till I have to add water again.
Good luck!! :+1:t2::sunglasses:

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Yeh im also doing a 5gal bucket, but with netpot height, its only 3.56gal! I see your point, thats too little.
But why would RDWC not have this issue? Or are you automatically assuming a larger volume?

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Larger volume of water means more for your roots to work with. Therefore, the transportation within the roots that takes place takes longer then it would in a 3 1/2 gal bucket.

If you had a way to change out the water, say 400 gph, then your basically constantly changing the water, 400 gal per hour. So, your plant is always being fed fresh water.

This is how I’m set up and will be getting a larger res next grow to help with the ph issues. It hasn’t been too bad but I want to have that much less trouble to worry about.
Hope that helps some.

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Thanks, I think I’ll try that. Is the black tube connected to a pump and the whites returns?

The black tubes hook to the pump which runs through the chiller and then into the res. Water flows through the white tubes into the totes.

I have massive PH swings in the early stage of flower in a 5 gal DWC but they even out. I had some early damage on the leaves from it but after a couple of weeks it starts to settle down. Im in the last week or so of flower and its been pretty stable, between 5.8 - 6.0.(I allow a bit of drift in flower as the slightly higher PH is fine in flower for P +K) It is drinking a lot less which is normally a good sign that its almost done and its shedding leaves like you wouldn’t believe! Its a WW Auto from ILGM. Lights have just gone off so I dont have a new picture.

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I ran rdwc…24 buckets and 2 res. I used about 80 gallons on a res change. I bought 4 perfect ph filters from Torus Hydro. They did not work for me…but they did fully refund all of my money and let me keep the filters for someone else to try.

That my friends is worth every penny!!

I have 2-35 gallon and 2-70 gallon perfect ph filters.


Cut the PPM in 1/2 and work from there.


In my case, the combination of these two, makes me believe I have a CalMag deficiency, which I had not supplemented to my RO water for the first 2 weeks!


Good Video. Thank you!

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I cut it down from 600-700 PPM to around 300. I had just started flowering so they are different nutrients(EH) and I stopped Cal-Mag altogether. I have continued to change out 1.5 liter of water every day with 6.5 PH water+ nut.till I get it to about 5.8 - 6.0
when I find it at about 5.0 PH in the morning.
This morning it was only 5.4 so maybe something is working. I am ordering parts to make a RDWC reservoir just for this bucket. I realize with the big root ball and the air gap below the basket I am down to about 2 1/2 Gal of water. About 10 perfectly good leaves have fallen off in last 3 days, not yellow just dried up and fell off. The new shoots look great though. I am a little concerned about the low PPM on the plant during flowering though. RDWC is a week away.

water temp 73-75f
room 72-77f deg
RH 60-70%


Sorry just saw this. You lowering the PPM to 300 should have fix the PH drop. Hows your plant?

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Sadly it turned out to be a male. Being so new at this I didn’t recognize those little balls till I posted it to this forum. Another member suggested it was too late but I kept the other three anyway even though they might be pollinated. Can you tell from these photos?

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