High PH, Help!

[Leslie]

I have a system that has been cycled since December. My PH has been high the last few weeks. I use well water to top off the tank. The PH out of the well is usually about 7.6. My PH had maintained around 7.2-7.4 until just recently. From reading other blog posts, I'm gathering it's probably my water, but I'm looking for advise, or troubleshooting ideas on how to determine that.

It may be a coincidence, but, the PH started rising after I added a plecostomus fish. I also added red wiggler worms two weeks ago.

I have several plants and herbs (kale, chard, buttercrunch, mesclun, micro greens, cilantro, basil, sage, oregano, thyme, and chives) All the plants are growing, but I'm noticing this week some of the leaves are starting to yellow. Is that the start of nutrient lock-out?

The fish seem to be fine. I have 16 tilapia, 150 gallon tank.

Another note, a few weeks ago, I had cleaned the pump. I have control valves on each grow bed that I turn off during cleaning. I had failed to turn one of the valves back on after cleaning. So, one grow bed was not filling for an entire week. None of the plants died, but I'm wondering if this could have caused the PH to spike.

I would like to add new plants soon, but I want to figure out the issue before I do.

Thank you for your time!

[Alex Veidel]

Leslie, have you used a pH test kit that tests past 7.6? If not, you probably are even slightly past the 7.6 mark....If you're topping off your system with your well water, it's likely the cause of why it's rising.

As far as the yellowing leaves, it depends on where and how they are yellowing exactly. Got any pictures? If new growth on the plant is yellowing while the veins remain slightly greener, then you have an iron deficiency, probably because of the high pH.

[Leslie]

Thanks for responding Alex. I do have a test kit, as well as an electronic meter, that tests higher than 7.6. So I feel the reading is accurate.

I'll have to take pictures to show the yellowing. I'll do that later today.

Thanks again for your time.

[Alex Veidel]

No problem. Also, are your growbeds media based and what are you using for your media?

[Leslie]

I'm using hydroton for my media. I've attached a few pictures of the plants.

What would be the best solution for maintaining a lower PH?

Thanks!

[Alex Veidel]

Thanks Leslie, that helps a lot. I think you're right. You've either got an iron deficiency or a magnesium deficiency. Iron is an immobile nutrient, so when the plant produces new growth, the new growth shows signs of deficiency, while magnesium is mobile, so the plant draws it it from its older leaves to produce new growth and the old leaves look deficient. I can't really see the whole plant in the third picture (kale?). Are the newer or older leaves yellowing?

[Leslie]

You are correct, it is kale in the third picture. The older leaves are yellowing, but now some of the new growth is showing it.

[Alex Veidel]

Sounds like a magnesium deficiency then. Or I could be wrong. I'm still a little new at properly identifying every kind of deficiency properly :)

Epsom salt is magnesium sulfate; relatively inexpensive and works great as a foliar spray. Throw a couple teaspoons of it into a spray bottle and apply it to your plant leaves. You can add it to your system water, but sometimes the presence of other nutrients tend to tie it up (calcium, I think...) I would also try to get that pH down to level, in case it's preventing your plants from uptaking iron. Have you ever added iron to your system?

[Leslie]

No,I haven't added anything before. I've only had plants for a month and a half now. So this is my first problem. How do I add it?

Should I use just PH down? Or is there a better long term solution?

[Alex Veidel]

pH down works great. Unfortunately, I have yet to uncover a long term solution...

You can buy chelated iron to add to your system. Sylvia sells some on her site:

http://www.theaquaponicstore.com/AquaIron-DTPA-Iron-Chelate-p/agsas...

Personally, I think I'm gonna start playing around with Maxicrop (liquid seaweed) as a temporary solution for missing nutrients (mostly 'cause I've already got it). My long term solution for nutrient deficiencies looks something like worm tea....

[Leslie]

Thank you for your time and advice! I really appreciate it.

[Vlad Jovanovic]

Hey guys, kale does need a bit more magnesium than lettuce and other greens (hence why eating kale is a good source of Mg).

Problem is at lower pH levels Mg deficiencies seem to be exacerbated, while at high pH's it's iron (Fe) that then tends to become locked out. In a nut shell, your immediate (and hopefully temporary) solutions are :

1) Lower pH and add a source of Mg (like Epsom salt or magnesium chloride salt)

2) Leave your pH as it is and add Fe. (An EDDHA chelate works well into the mid 8's pH level. The DTPA that Sylvia sells should work alright at your pH levels though).

3) Add both regardless of whether you choose to lower pH or not (I'd probably drop the pH and add both, but that's just Me)

You could with either one (Mg or Fe)use a foliar spray and get locked into a regime of spraying (which is fine). Just use some kind of anti-fungal in the spray mixture so you do not invite pathogens by having excess free water on the leaves.

And be aware that Mg deficiencies are a bit harder to correct as opposed to Fe (should that little tid bit calculate into your decision is up to you :)

[Sonja Martin Young]

Alex tell us more about your idea with using worm tea and maxi crop. How much and are you using it in your water or as a foliar spray? My worms are making a lot of tea and I would like to use it the best way possible. Thanks

Alex Veidel said:

pH down works great. Unfortunately, I have yet to uncover a long term solution...

You can buy chelated iron to add to your system. Sylvia sells some on her site:

http://www.theaquaponicstore.com/AquaIron-DTPA-Iron-Chelate-p/agsas...

Personally, I think I'm gonna start playing around with Maxicrop (liquid seaweed) as a temporary solution for missing nutrients (mostly 'cause I've already got it). My long term solution for nutrient deficiencies looks something like worm tea....