ph of water in reservoir for recirculating drip system keep rising up

Hey all, I've just setup a recirculating drip system 2 days ago and I've noticed that the ph of the water in the reservoir keep increasing every few hours. The water I use were allowed to sit and stabilise for 24 hours before I mix the nutrient solutions in, and the growing medium is coco. Is this rising ph a normal thing? or is there something wrong if I have to adjust the ph twice a day?

what nutes you using? and how much is it rising? and how small is your res?

I'm using this nutes called growrite A + B. I'm using a liquid drops ph measurement at the moment so I can't tell exactly how much it's rising by but it usually goes from below 6 (above 5.5) up to almost 6.5. The reservoir is 25 litres.

a small res can be harder to keep ph stable, you should if you can get a ph meter. but drops work to, 5.8 should be your target. but 5.5 to 6.0 should be ok
having to adjust is normal but more than a couple of points per day leads me to think you have somekind of problem. is there anykind of slime or visible bactira?
that kind of thing can cause ph to rise. things that could help if there is something in your water are H202 7 ML per gal and a good air stone in your res, and
keeping your res below 74 also some nute brands have a ph buffer in then and that could help stablize it to,

thx guys, can i get h202 in any hydro store? I have noticed the water in the reservoir kind of have foul dampy smell. Could this be a sign of bacteria?

This is the exact reason I always use Nutrients made for COCO. If not the PH will go wacko. Plus I never recirculate the nutrients. Always drain to waste. But even if I was to go with a recircilating rez, I would go with Coco Specific nutrients. I have used a few nutrients that worked in coco, with out trouble. But others just go freakazoid on the PH. Check the PH of the run off. If it is not what you added then change nutrients.

This is just my opinion. But I have had this same trouble with Coco, and it was the nutrients I used each time.

Hi lord, would u recommend me switching to drain to waste system? If i do would that fix the ph problem cuz the waste is not being mixed with the nute solutions again? Or will the nute change the ph of the coco itself? One more thing, in a drain to waste system, is an airpump crucial? Thx in advance

I think what hes saying is first check your run off and if it dont match what your res is then you need to change the line of product of nutes
and get one thas coco compadible, sounds like a easy fix

Coolio, will do that tonite. Hopefully that will tell me what to do.

Yes, what Hellraizer said.

I have some Non Coco specific Nutrients I am useing up. I use them on my mothers. If i feed the mothers at 5.8 PH, over time the Coco builds up to above 7.0PH, as does the run off. So to counter act this I have to feed the mothers at 4.3-4.9 PH, so that my run off and coco are closer to 5.8 PH. Only reason I am doing this is because I do not have to worry about screwing up my yield, and I want to get rid of this nutrients. If it was not a 3 hour drive to get more nutrients, I would not be going through this hassle.

Once you find a good Nutrient that keeps your PH stable, you can run a recirculation system. But until then I would run drain to waste. Flush them twice a day with nutrients with a low PH, continue to monitor the run off until it is between 5.3-5.9. I shoot for 5.7-5.8. Remember, it is about impossible to over water with Coco. Once you have the PH is the desired window, make sure to keep checking it for a while to make sure it does not once again spike on you. If you stay with the same nutrients, you might find that you need to feed them at lets say 4.8 PH to have a run off of 5.8. But This is not that good of a way to go. because the coco might have hot spots in it for PH. This is why I always suggest going with a Coco specific Nutrient. Even after you change nutrients, it might take a week or so to get your PH to fully stabilize.

This does not mean that ALL Nutrients that are not coco specific will not work. But it is like playing craps. It is a gamble which one will work and which one will not. I have been useing Canna Coco Nutrients, but will be trying CSN17 by Botanicare soon. I have heard a lot of really good stuff about this product. If you go with the CSN17, make sure to get the COCO specific product. they have more then one.

I have found over the years that chasing pH is more counter productive. What you need to do is pick a range of pH that works for your application and stay within that range. So lets say for you 5.6 to 6.6 should be the target, much easier than standing on one number. There are all kinds of reasons pH will drift up or down and that depends on how your growing. I think there is some good advice on getting your nutrients dialed in above, hope this helps.

5.6-6.6? That is not the correct range for coco. 6.6 is to high and he will get some nutrients to lock out. I do not think he is worry about a couple of points, he is worried out the full digit increases, which he should be. If he is clear up at 6.5 like he says he is, he is going to start getting blachie fan leafs that will start dieing off, and the buds will form slowly and not fill in on him. He needs to keep it between 5.2 and 6.0. This is why I told him 5.3-5.9. Even though Coco has all the benefits of soil and looks like soil, does not mean it needs the same PH as soil. But those PH numbers seemed a little low for soil also. But to each his own.

I have been growing with nothing but Coco for about 4 years now. For me, it is by far the easiest medium to grow in, but the PH is very important. You use a PH window of 5.6-6.6 and you are going to have some very sick plants. At least I know I would. but maybe you use a Nutrient that reacts differently then the ones I use.

The meduim I use is grodan water absorbent. Anyways unless you totally saturate your meduim with a low ph at the very begining to bring the ph of the meduim down, you will have quicker ph up levels. When the water recirculates the ph will go up naturally as the plant uses it or whatever. But yeah I didnt saturate my veg meduim fully and every time it recirculates the ph shoots way up. Its about 2 weeks now and its finally starting to slow down. Dont sweat it if its vegin, but if you transfered to bigger pots or whatever with new meduim for flowering, unfortunatley u got alittle wait on your hands. My veg cycle is fine dark green and plenty of new growth and I only ajust it once in the morning and once at night. Its just not optimum plant absorbten in my opinion.

lord: I changed to drain to waste system and checked the ph of the runoff this morning. it was about 7 when the reservoir in the morning was about 6.2 or so. Seems like it's time to head to the hydro store lol. The plant itself still looks green and healthy though, how long does it usually take till it shows something is not right? btw, I just realise how much solution is wasted on drain to waste. My 25 litre reservoir will only last me 2 days at this rate :O

tam: I flushed the pots of coco with ph'ed water three times before I transplanted, unfortunately still doesn't stabilise

Damn I thought it was a no brainer. Somewhere in the system there something your not realizing . I hope you solve it , drain to waste is such a waste of money, good luck man.

Rizou, you can flush them with a really low PH if you want of like 4.5. I would not go much further below this. Also, if you are going to run a recirculation system with Coco Coir I would get a filter sock for the pump. If you are going to run a recirculation system with Coco, A coco specific nutrient is about a must have. Once you get the PH to level out, I would shoot for a PH of like 5.4 on the nutrients, this will give you a .6 buffer window before you should adjust. I am sure once you get better Nuts for your Coco, you will get this dialed in and find it very easy.

Tamorin, he is useing Coco, not rockwool. Rockwool has to be flushed and conditioned before it is used. High quality Coco does not. If you are buying the cheaper bricks of coco, I would flush them because of the high salts in it. Coco has a neutral PH level.

Got coco specific nutrient! I'm gonna run drain to waste from now on after reading on the benefits of it. Thx alot for the help lord, +rep!

Rizou, How many plants do you have? And how big are the pots or grow bags or what ever you have them in?

A well-balanced recirculating system will have the PH climb slowly over time as the plants uptake the (acidic) nutrients from the water. In my 25gal RDWC/Drip hybrid system, I see an increase of approx. 0.1 - 0.3 PH per day. I offset with a small amount of PH-down once every couple days. I've had fantastic results.

Nothing to be alarmed about unless you are seeing much faster rising PH, which could be an indication of something else upsetting the balance.