Constantly rising PH level

[Guest Wilderbud]

My PH rises to alkaline every day in my flood and drain setup with expanded clay as a medium. I am worried about this because I think it should only be a weekly occurence.

 

Should I discontinue using my tap water and stock up on distilled or is adding 1ml of PH down every few days for 20L of water OK [i let it stay alkaline for a few days]?

 

OR, if you think this isnt a good situation could I dump the water every fortnight instead of getting distilled or is my tap water a big problem? Ive added about 5ml of PH down to the 20L and havent topped up the reservoir yet.

 

PS. Im using liquid tester but I used the same kit last time and adjusted it weekly - it was different tap water then.

Edited November 26, 2003 by Wilderbud

[Guest Wilderbud]

Another thing about tap water... if tap water can be useless for growing if its too dirty then how much is a decent enough filter?

 

I have a kind of filter on my fridge [has a water + ice machine on it] that isnt hooked up so I might be able to use it - hmm.

[Luke Skywalker]

What ph is your water when you add it to the tank, what is your nutrient brand/type and concentration, and have you been flushing the system weekly? Do you know what e.c. the tap water is by any chance?

 

Try and keep the system running as smoothly as possible, the more the ph jumps around the place the worse the plants will grow, niiice and even is the way to go. How often are you topping up the reservoir with fresh ph adjusted water?

 

PH levels should slowly drift upwards, but only by a couple of 0.1 increments at the most in one day, and no more than that. If it's jumping more than a half point in one day, then you should review the system, as something is going wrong somewhere.

 

I use a float valve and feeder res, and I keep the feeder res filled with ph 5.0 water rather than the 5.5 which the main nute tank is at. This is so when the tank is topped up automatically after it drops, the water is kept at about the same ph level rather than jumping up. It can take time to get the right levels for your particular grow, but you can usually get by by keeping the feeder res half of a ph point below the nute res, and the nute res should stay fairly stable.

 

And you are flushing and replacing the entire nutrient solution every week or so aren't ya?

[Guest Wilderbud]

Luke, Im poor and new at hydro so I have no idea what the EC is of my tap water and dont know where I get it checked. The PH of the tap water is 8 according to my liquid PH tester [its all I can afford - I was using old iodine before and it showed as 7 on it].

 

I havent topped up yet as the greens are only seedlings still - the water level has gone down about 1L each week and I changed the nutes last week although I didnt flush the tray at all [theres a bit of salt residue so Ill do it again soon].

 

Im using a cheap hydro solution becasue I only had enough for that at the time. Its NPK is 23g/L:9g/L:17.5g/L and its made by R&D Aquaponics Chemicals from NSW. I can probably replace this next week for the General Hydroponic 1-part nutes if it could be the nutes. Im using the cheap nutes at 2ml/L like it says.

 

I jumped in to hydro too soon but I really want to finish growing these plants but its hard to test things or fix them with limited funds. Im fairly sure this PH is a problem because I didnt get this much variation before - I dont know what to do to fix my hydro system.

 

Is litmus paper more reliable or would a nursery or spa shop test my EC/PH?

 

PS. I never knew EC was important until I heard you guys using the Truncheon.

 

My plants are growing slower than a soil grow so this isnt very nice.

Edited November 26, 2003 by Wilderbud

[budsta]

I have a recirculating system & it is normal (in my exoerience) for ph to climb.

I flush every 2 weeks & find it takes a few days for the ph to settle after flushing. I often keep topping up with ph down.

Did ya give the expanded clay a good soak & rinse before use?

I have found some mediums accelerate ph rise if not thoroughly rinsed firstly.

I also keep my res about 5.5 (about 5.8 - 6 for flower 5.5 for bloom)

 

I have had no problem with tap water, in my area it is highly chlorinated & has a high ppm but plants still thrive. Maybe check the ppm of ya mix too, as I find this rises too (especially getting near to flush time)

 

Gro good...

[Guest Wilderbud]

My clay balls were thoroughly washed in a bath of PH neutral water to get rid of dust.

 

I dont think I can test EC/PPM/PH properly at this time but Im willing to test my tap water if someone points me to a place thatll do it [hydro shop? - duh if they do].

 

BTW, when I misted my plants they went glossy and curled up at the edges so I havent done it again - this is with straight tap water [new Selectaspray mister too].

Edited November 26, 2003 by Wilderbud

[white_cluster]

if your plants are under HID then dont mist them unless lights have gone off or they'll burn up.

 

I got real bad water, my advice is to deal with it and not buy a RO filter, do more water changes, I find my water lowers pH the first few days then it starts dropping, I just do more water changes to solve the problem.

 

them nutes are fine its just what happens with hard water. I change my res when half the original water has gone.

[Luke Skywalker]

Yeah, take a bottled sample to a hydro shop of your runoff, fresh water and nutrient, and they should be able to test it for ya. If they don't, go elsewhere, they obviously don't give a stuff about ya.

 

Hydroponics ph is needed at the 5.5 - 6.5 level, not neutral. Different absorbtion rates in water culture to soil, as you don't need the soil biota to process the nutrients into absorbable plant forms. Flush the media, and I mean flush it several times, until there is absolutely no discolouration to the water. Make sure the water is 5.5 or so, otherwise you're basically setting the clay at a high ph, and the sys can drift too high to quick.

 

I've never heard of that nute you're using, but I hope you're not using it at full strength on seedlings. If so, drop the rate to about 1/3 to 1/4 or so, and slowly work up as you go along. Get a good, liquid, mj specific nute mate, there's nothing better and simpler than that. You'll just be stuffing around otherwise.

 

Yeah, I'm a poor bastard too, so I got my truncheon over time, 10 bucks here, 10 bucks there... layby is a great thing. I suggest you'd do the same, as it's a fantastic tool for hydroponics.

 

As to the ph tester, get a canna or flairform liquid ph test, about 5-8 bucks or so... these are designed for use in hydro, and give very accurate readings. Just remember to look at the colour in natural, rather than hid light, as it can skew the colour somewhat. You're aiming for just a tinge of orange in the yellow, or a shade under 6.0 You must flush the media weekly... salt buildup is going to slowly kill the plants otherwise. You'd be absolutely horrified at how high the e.c. can get if you don't....

 

Hope that helps WB.

[Guest Wilderbud]

I have a Flairform PH tester.

 

I definately bathed them in neutral PH - It took about 10ml to get about 100L down to PH7.

 

How many cycles should I flush with straight PH5 (?) water?

 

Also, I noticed the Sulphur level in this nutrient is 10g/L so its up there with the macro nutrients - does this sound right? It doesnt really matter [itll be replaced soon] but it may be the reason I have slight salt builtup after only a week of nutes - hmm.

[Luke Skywalker]

I definately bathed them in neutral PH - It took about 10ml to get about 100L down to PH7.

Yeah, this will mean your sys is set at neutral, which is too high for a hydro system.

 

How many cycles should I flush with straight PH5 (?) water?

 

Just run about 3 times the volume of the container the plants are in, you can just use a 10l watering can. That should help set the ph at a lower level. (Make this flush to 5.5, not 5.0) Test the runoff afterwards to see if it's staying stable as it goes though or rising. Then set your nutes at 5.5-6 and they should run much better.

 

Suphur is sometimes called a secondary element, along with calcium and magnesium, although not always. I'm not certain that that's going to be a bad thing, but just to be certain I'd be running it at 1/4 to 1/3 of full strength to be sure. You should be doing this anyway, as seedlings will quickly burn otherwise. The salt buildup is normal, this is why you have to flush the system every week or so, otherwise this buildup gets ridiculous and begins to poison the plants. Insoluble or bad quality nutes will also make more deposit than good ones, so make sure it's at least decent quality. Otherwise your plants will be limited by the food they get. I cannot emphasise the need to weekly flush the system with a watering can of 5.5-6.0 water. This is crucial in media based hydro for a stable growth environment.

 

Hope that helps ya buddy.