Backyard Aquaponics
A place to discuss aquaponics

I am currently running rainbow trout. At 700 mg/l na, that's less than 1/5 teaspoon per litre. Doesn't sound like much to me. I will look up hydroponic recipes tomorrow.

oh u need brackish water umm I see I see. but still they seem to be able to survive in fresh water too.. well fresher water as well

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Yes and my salt levels have been much higher while I was enjoying better growth. There's something else going on.

well to bring up your potassium without affecting your ph ill suggest using potassium sulfate. it must be atlest 1.5 times your nitrates. everything is modeled around nitrates cus its literally the building blocks of all matter i.e. proteins. so try that. but one thing to note not many crops can be grown at those levels of Na and Cl especially water crops like cucumber and watermellons. there is no physic difference in a plant grown in soil compared to soil less media. all that different is nutrients availability and contact time with roots

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sry I meant to say many crops like cucumber and watermellons cannot be grown in high salt content medias

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http://www1.agric.gov.ab.ca/$department ... /agdex3303

read this.

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Are you actually telling one of our most successful APers that he does not know what he is doing? with all of this chemistry talk, you sound like you should be the one doing hydro instead. The salt was added to mitigate disease. Most well running systems will get salted up from time to time. Now there is nothing wrong with getting your water analyzed, just don't try to chase the numbers. The system has this wonderful ability to balance itself out.

Thanks ronmaggi, that's a really good point. There is a remarkable difference between chemistry and a biological system. I started my life as a biochemist but horticulture is my hobby and I have learnt many many times that you can't treat it like a test tube, it's just so much more complicated than that.

Having said that I think cookie may be right about the salt and the curcubits. My biggest problem is the watermelon that germinates but then shrivels and the cucumber are getting leaf burn. My spaghetti squash died at the 2 leaf stage. Brassicas seem fine but they like salt.

So today I'm going to use some if the AP water on my garden and refill. Shall post what happens. I won't be rash, might do a 20% water change using dam water.

Salt generally serves two purposes in an AP system.

1. protect fish against nitrite. REALLY needed when cycling but not so crucial later.
2. to help fish deal with a fish disease outbreak. Since this works best when you shock the pathogens by suddenly adding a lot of salt 3ppt or so. The fish can osoregulate such a jump in salt concentration but the nasties can not.

Once you have given the nasties a shock there is no real need to keep that much salt in your system so getting rid of it is not a problem but most people just let that happen over time. I'm pretty sure that others have grown cucc and melons with a bit of salt in their sysetm but strawberries really don't like it.

Ryan would probably be a better person to talk to about melons and salt.

Strawberries certainly dont like 3000ppm NaCl but mine are growing very well, currently sending lots of runners out, at <1250ppm. My cucumbers are also growing well, with lots of flowers ATM, at <1250pm NaCl. Button squash and jap pumpkins are in the ground, but being watered with my system water, and both are growing really well.

My strawberries are fine but everything else is doing poorly. Mostly stunted growth.

So not salt then

Nope. I think I may be phos. Contrary to popular belief that phos def is rare.

cookie Shadow Benny looking real nice

Ive ran 3ppt (3000ppm) salinity since forever and the only plants Ive ever had issues with is basil and strawberries.