Ok boys and girls here is a topic Id like to hear more thoughts and pros and cons for.I was thinking last week after reading some post.I saw few either way pn this but want to see more and reasons why. Some say its fine to top a res off with more ph balanced water others say dont as the nute strength will be off and you wont know which nutes are off maybe the nitrogen maybe the phos.I can understand this but to those who dont top off with fresh water how do you control the ppm rise rate?Alot of times my plants will drink more plus evaporation in an aero setup which can cause the ppm to go from 1400 to 1700 how do you bring the ppm down without topping with water? Lets see what people say..Thanks

That's a good question?Iwant to here what everybody take on this. PEACE

Yeah, good question, but I don't think that you'll get much discussion cause most folks just know a little about it.

First you have to specify whether chemical or organic nutes. Most hydro growers use chemical, since hydro-organic requires some experience.

I'll just say that when using organic nutes, you can top off with plain water or a weak nute solution or a reg-strength solution, depending on your res maintenance method, and leave it at that.

For chemical nutes, if you use a TDS meter, it's easy to see the daily rise in ppm with no topping off. When you add plain water, to raise the amount to original level, the ppm is close to the original level too.

Even if you don't measure ppm, it's easy to maintain a res. When you mix a new batch, just mark the full line of the res. When you maintain the res, just fill with plain water to the full line. When you've added back the same amount that the res holds, it's time to change the res.

HTH

__________________
Problems on the forum? Contact me here!

I trust your opinion and I respect it more than a lot of the others on here.

Going from what you have just said then, would it be ok to keep a nute tank running for 4 weeks and topping up with water or nutes to keep it constantly at the desired ppm level or would you advise me to just top up with water for 2 weeks and then dump the tank with all the nutes in and start fresh so the ratios are more evenly balanced, would dumping every 2 weeks provide that much better results.

Depends on the size of the rez and the number of plants it is supplying- and that's a rather inexact science. On-the-job-training will reveal a lot, tho.

If the tank size is fairly closely matched to the usage requirements of the batch of plants it is supplying, as water level drops, the ppm will remain close to the target ppm for a fresh tank. If such a tank is topped up with plain water, the ppm will drop, corresponding to the nutes depleted from the solution by the plants.

If the tank is somewhat too small in volume for the plants' water usage requirements, ppm may rise a little as the plants use the water. In that case, adding plain water to the tank will return the ppm close to the mix target, although ppm will drop a little according to what the plants have eaten.

I have both situations; my mother system has a ~50L tank, but at the moment is running 10 bushy mother plants which suck a lot of water. The nute ppm rises as water level drops. If the tank volume were greater, the plants would use a smaller percentage of the tank volume each day and the ppm would not bump so much. I'd use a bigger tank there if it would fit under the tray.

My flowering systems, each running 125L tanks and supplying ~20 plants each, seem to maintain ppm within about 5-10% of 1500 for a week at a time, depleting about 25-30% of the volume of the water in each tank. Means the nutrient consumption is very close in % to water consumption.

__________________
Get a harvest every 2 weeks - A batch of clones in rockwool - Al B. Gone

I'll go with whatever potroast says thanks al, i trust his judgement.

ngt, the sky is blue.

__________________
Get a harvest every 2 weeks - A batch of clones in rockwool - Al B. Gone

Great- glad you agree with me.

What I wrote concurred precisely with what potroast said and expanded upon it.

I gave you the blue sky bit so you could have something I said that you would be sure to disagree with.

__________________
Get a harvest every 2 weeks - A batch of clones in rockwool - Al B. Gone

Your trying to make this some kind of competition, but i couldnt care less and your not going to wind me up.

I trust in what potroast says. You I couldnt give a toss about but hey ho.

Hey, thanks Bro! My response just summarized some basic res maintenance, and Mr. Fuct's answer goes into what really matters, the size of the res, and how much of it is used for each irrigation. The larger the res compared to what is used, makes for more consistency in strength and pH.

So for your situation, how big is your res, and how much of it is used to flood? How often do you top off? Do you measure TDS?

The easy way is to mix a fresh res on a regular basis, that way you know that your plants are always well fed.

HTH

__________________
Problems on the forum? Contact me here!