My EC reading always goes up... WTF

[mattdestruction]

Hey guys,

 

Well, I have an EC meter but I'm not quite sure how to use it. Calibrated it like the guy said and wouldn't you know, it seems to me that my plants don't take in any nutes. I threw in about 1/4 strength for the guys in flower and 1/8 for the mothers and veggers, however to this day the EC reading has only increased, and it's been about two months. I have to add more RO water every day just to keep the meter from jumping .10ms and I shoot for a reading of 1.0ms for the flowering guys and .5ms for the veg. Before this (I guess I was over nuting) I was changing the water every two weeks and using nutes at twice the strength since I couldn't see that the plants weren't taking them in.

 

After buying the meter, I just tried to use less and less nutrients until it got to a level where the EC reading didn't jump up by the next day, but that level didn't seem to exist beyond the .10ms jump. Is this normal? Do I just not know how to use the EC? It's currently out of batteries and I can't find anyone who sells the right kind so... might be back to my old ways.

 

Anyhow, any help would be much appreciated.

 

Peace

[nitram]

More infor is needed from you mattdestruction

 

What 'style' of grow (hydroponic/compost)?

What medium are you using ?

What nutrients ?

 

Most importantly what EC meter ?

 

Which EC reading(s) are rising (plant/grow discription)

 

How did you callibrate your EC meter ?

That should be interesting reading ?

 

U sure you don't mean PH meter and PH readings are rising ?

 

I'll leave it at that till you come back

 

After buying the meter, I just tried to use less and less nutrients until it got to a level where the EC reading didn't jump up by the next day, but that level didn't seem to exist beyond the .10ms jump. Is this normal? Do I just not know how to use the EC? It's currently out of batteries and I can't find anyone who sells the right kind so... might be back to my old ways.

 

EC meters come factory calibrated

To use:

 

(1) dip in plain water (res) Tap water fluxuates in regions but is low (EC <0.2 - 0.4)

 

Make up you res with nutrients. Check EC and addjust acordingly.

 

Check PH and adjust accordingly

 

Keep res airated.

 

cheers mattdestruction

[thc24]

hi mate quite normal in a recirc set up, either top up with water OR mixed fresh nute slightly weakerand once a week do a complete res change.

 

For stable nute you only get that in run 2 waste or a set up where nut isnt reused. In recirc the plants are taking water from mix making ec stronger.

 

 

your right mate just need to learn the ins and outs of your set up.

 

Batteries dam you must have left it on mine last a year or two. conbtinue using ec meter, your ec sounds pretty low must still be in early veg.

 

example when i ran a recirc in clay/rock wool i started cuts at 1,8 ec and flowered at 2.2ec for full sized plants.

 

5 day res changes would be ideal as you can see a recirc is quite labour entensive and PH/ec need to be checked daily half the reason i swapped to a set up where fortnightly to monthly res change with fresh nute every feed in coco. this may or may not suit you, if your recirc is a satelite style there is little differance to run2 waste only medium (coco or rock wool) and waste water doesnt return to res but returns to seperate catch container that is thrown or reused in home garden.

Edited July 17, 2006 by thc24

[mattdestruction]

Everything I'm doing is hydro with fake-soil plugs instead of rockwool, thoroughly cleaned (and re-used) hydroton, and the nutes are the GH 3 part for RO water. My hydro setup is an Ebb and Flow table, one for flower, one for veg/clones/mothers.

 

My EC meter is a black Milwaukee pen (it's definately an EC, not a pH). The guy at the store gave me a (I think...) 1450ms calibration solution that I dipped the pen into and spun the calibration screw until the reading matched the solution. I have also been cleaning it once a month with this A+B cleaning solutions.

 

The EC readings rise slightly each day so I top off the buckets with regular RO water to try and get the EC back down. I have found no proportional amount that the EC changes when compared to the water level drop in the res. I try to keep my veg/clones/mothers at about 400-600ppm while the flowerers at below 1200. My plants have always kind of looked unhealthy, and I attributed this to nute burn, but they don't seem to be looking any better now, so I may have a pH problem since I have no way of checking that (however I heard that the GH 3 part nutes have a buffer in them to set the water to the right pH).

 

Unfortunately, the current circumstances dictate that I can't really change the res more than once every two months, which the guy at the hydro store said was OK as long as I was monitoring nute levels with the EC meter, which is why I bought it in the first place.

 

I hope this is clear, I'm kind of out of it today... drinking Monday nights is a surefire way to ruin your Tuesday.

 

Peace

[Luke Skywalker]

Every two months is entirely too long, and you need to flush with fresh pH adjusted water each week before making up a new reservoir. The most you would ever want a recirc system to go without dumping and reformulating is two weeks. One week would be far better, and is what I would generally advise for a recirc system.

 

The E.C. will also rise in recirculating systems as the plants exude waste substances, but it's almost impossible to work out an exact proportional change as far as water use compared to salt levels go, as the plants take up different nutes at different rates at different stages of their cycle. The problem here is the reservoir though I think.

 

I would seriously question anyone who says it's okay to run a recirculating hydroponic system on the same reservoir for 2 months. This is why you've had burning and sick plants.

 

I would also advise to only use an inert media for cuttings and seedlings like rockwool or perlite, or even water cloning, for a recirc system, certainly not something like coco (which is what I assume you mean by fake soil. If it's something else could you give some more information?)

 

Finally, flush your system with fresh pH adjusted water (you can use a mild solution if you like) every week, and keep flushing this until the water draining out is at an e.c. level just one point above what you put it in at. i.e. if you flush with e.c. 0.8, then flush until it comes out the drain at e.c. 0.9. This will show that all the build up has gone.

[pipeman]

It is normal for the ec to rise in a recirculating system because the water you use has a certain % of useless salts. Although these salts are not absorbed by the roots they still effect the point at which nute lockout occurs. For example say you had a plant that could cope with about 1.8ec you could provide that plant with more nutrients using water with a starting ec of 0.2 than water with a starting ec of 0.6. I don't think I explained that very well, but I hope you get the point...

 

So, as the plants uptake the water and useful nutrients these useless salts are left behind so your ec reading goes up (same amount of salts in smaller water volume), so after one week you add plain water to bring it back down, then the plant drinks more water. So after the 2nd week you top it up again with plain water to bring the ec level down. Each time this plain water contains more useless salts. You see what is happening? Gradually as the plant takes up the water and useful nutrients it is leaving ever increasing amounts of the useless salts which were contained in the starting water.

 

As the amount of these salts in your system increase of course it decreases the amount of nutrient you can add, which either results in your plants starving to death either through lack of essential nutrients being present or suffering nute lockout.

 

and of course, you need a ph meter they are mandatory for recirculating systems that could also be your problem.

 

I have seen bubbler grows go the distance without any water changes just topups (with 1/4 strength nutes all the way). You can get results like that if you're careful, but generally your plants will be healthier the more often you change the water. But you never know, you may get your PH meter and once you get that right may find the way you are growing works well enough, because as you are using RO water res changes are not as important.

Edited July 18, 2006 by pipeman

[mattdestruction]

Thanks for the info guys. I really hate that I can't change my res more than once every couple months, but my plants and I are on opposite sides of the world, and the people taking care of them are only doing so begrudgingly. As I see it, once every few months is better than not at all.

 

I didn't know that plants left behind waste in the water, I thought they just converted whatever salts were in there into glucose and/or Oxygen. Now my situation makes more sense.

 

Can the waste salt do anything to harm the plants? I think I've heard that they can cause lockout and just clog pumps and stuff, thankfully all my tubes and pumps have a pretty big diameter.

 

The media for cuttings is inert, it's not coco choir or anything else I've ever seen at another store before. I just call them soil plugs because that's what they look like - soil-like corks with a hole down the center for plants. I've had a lot better luck cloning with these than rockwool, as they don't need to be soaked for 24 hours or pH adjusted. Additionally, I've heard rockwool lowers pH over time while these do not. I'm not exactly sure what they are called, but they come in large bags and stay moist without developing mold.

 

Anyhow, I'm off.

 

Peace

[Luke Skywalker]

Never heard the lowering pH thing with the rockwool.

 

The wastes aren't necessarily salt ions, although they are a component. They can harm the plants in the same way it would harm you to have a nappy on and never change it.

 

Adding beneficial bacteria or enzymes may help with breaking this down and preventing too much damage.

 

Do the plugs you're referring to call themselves jiffy pots? I'd be most interested to see a photo if you can upload one for us...

[Shithappens]

just FYI i use a mixture of systems but its generally recirculative and i also see the changes the babies go through.

 

The plant takes what it needs when it wants it. You can chuck all the nutrients at it you want but hell it will only take what it needs. I run my CF at from 18 to 20 and dont care if it drops below the 18.

 

My system is an 80 litre nutrient tank with a float valve being filled to the 80 mark with tap water that is from another 80 litre tank. This gives the topup tank time to evaporate the clorine out and become more plant friendly. All i do is topup the topup tank as i visit them (I should plumb that up but then i wouldnt have to do anything)

 

The topup tank provides a balance for my CF as when water is lost it balances it stopping any chance that it can rise to a harmful level.

 

I change my tank monthly due to being a once a week guy with the best feed lawn out. since changing and adding the topup tank i have noticed virtually no decrease in the yield but have noticed slight imperfections appearing near the end of the month like blemishes on lower leaves nothing major.

 

I could do it every 3 weeks but then i cant use the months as a reminder to do it and i would get all confussed.