Aquaponic Gardening

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Greetings everyone. I purchased a system from Sylvia many months ago, but had to do some prep work before going ahead...that prep work being, getting a greenhouse up. Well, that's finally done, and this past week, I assembled the whole thing, filled it with water, and am now in the process of cycling it.

Yesterday was day one. The setup is complete and operational. The unit is in the greenhouse.

On day one, I added the dry mix included in the cycle kit.

On day two (today), I first tested the ph (8.2) and the ammonia levels (8ppm). Immediately after this, I added 5ml (2 tsp) of ammonia from the cycle kit. I did not check ammonia levels after this, but it seems to me that I was already starting out with 8ppm of ammonia, that adding ammonia would boost the levels even higher… I assume that as nitrites and nitrates climb, ammonia will go down? At what levels should I be concerned with if ammonia keeps rising?

2. I was watching one of Murray's videos, and the question I have is… Is the ideal way (with a flood and drain system such as Sylvia's) is to fill the grow bed up to about an inch under the top layer so as not to expose the top layer to water… thereby inhibiting algae? Then if so, and I had a better timer, would it be better to simply allow the water to reach the desired level, and then to have the timer switch to off? Or, is it better to allow the water to flood the bed for a full 15 minutes?

Thanks! and I'm sure i'll have many more questions.


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I'm sure my well water is to blame... but algae may also be part of it.

There is some silt accumulation (blackish sand with silver speckles) in the bottom of the ft that may be to blame. I bought a German made vacuum that is getting a lot of it out. It takes time because the silt gets stirred up when vacuuming.

I also bought another bag of hydroton to top off the growbed. Looks like the top layer of media was always wet and possibly contributing to algae growth, which would bring up the ph.

This is like a high school chemistry experiment ;-)


If algae is causing you a high pH in the later afternoon, get up before dawn and collect a water sample and see if the pH is lower just before dawn.  If Algae is causing you pH issues you will see diurnal pH swings where the pH drops overnight while the algae uses up dissolved oxygen and gives off dissolved carbon dioxide (which will act as a weak acid in the water overnight but then the algae takes that back up during the sunlight hours so the pH will rise during the day.)

The shading of the ft, along with the shadecloth over the greenhouse seems to have helped quite a bit.

The bluegills are finally home!  I was quite concerned because the water in the ft at school was about 6.4 - 6.6, and the water in the tank at home is about 7.6

I brought them home in a Coleman cooler with airstones in it.  They did great!.  It took me about 2 days of exchanging water back and forth to slowly bring the ph up.  Finally in they went.

Now what's interesting is, one of them got left behind at school.  A real hider that one. So, I brought him home in a bag with air trapped inside.  Didn't want to do the whole 2 day gentle approach, so, in he went.


No floaters yet...  They're now snapping when I feed them. Ammonia and Nitrite levels near 0. Nitrates 80-160 (can't seem to get them down). Ph around 7.4 - 7.6 


Added chelated iron about a week ago.  Not seeing as many spotted leaves, but lots of leaves still turning brown and drying up. This is evident on the basil, oregano, and watermelon. The cantaloupe and tomatoes are doing great however.


Going to start some new seedlings today I think.  I am hoping that as the system matures, the ph will come down, and when that happens, the plants will be able to uptake more of the nitrates.  Is this correct thinking?



TCLynx said:

Shade the fish tank, block the light and the algae shouldn't be a problem, I wouldn't struggle with removing it, once it is shaded out you actually kinda want the algae to get pumped to the grow beds to decompose and provide the chemical compounds that will help inhibit more algae growth in the future.  A small amount of surface algae isn't a big deal, you just wan to make sure to shade the system so you don't get pea soup.  If the sediment is major I think there are ways to siphon or pump it out but a very small amount is probably nothing to worry about.  Just make sure you are not getting a muck of fish waste or uneaten feed building up anywhere.

I've run systems that have a pH of 7.6 long term and the nitrates tend to run high and I have to add chelated iron regularly but the systems still work.  In cool weather watercress does great and even substantially brought the nitrates way down in my big system (Watercress likes alkali water.)


If there is nothing in the system causing the buffering (shells, limestone, marble, concrete, mortar, etc) the system is likely to come down in pH over time.  However I've seen my systems with regular top ups from my well water manage to maintain a pH between 7.0-8.0 depending on the amount of topping up during a hot dry spell.  If your well water is causing the high pH you might want to collect some rain water and use the combination of source water to help maintain the correct pH. 



When you say you add chelated iron regularly, how often is that, and how much do you use?

I've been adding about a cup full (distributed through all the grow beds) to my big system which is about 1400 gallons of gravel and I probably should be doing this once a month but I get lazy and it some times goes 6 weeks between when I finally decide the plants are screaming at me loud enough about the deficiency.

Hi Jim,

Adding iron will depend on the types and quantity of plants in your AP. To avoid over supplementing, add small quantities every other day until you notice the health of the plants getting optimal, the quantity you've added is the amount you should add monthly generally but this will depend on if you add/subtract/change plants in your AP system.

Jim Logios said:



When you say you add chelated iron regularly, how often is that, and how much do you use?

There are some plants that will be quick indicators to let you know when you have waited long enough between doses.  My oregano tends to show the Iron deficiency quickly (The yellow leaves with green veins in the new growth) and I've also noticed nasturtiums will show Iron deficiency pretty early too.

If your still having overheating issues I heard silica drastically helps plants cope with hot weather among other things. I live in Canada, and I know it defiantly helps with the cold.

im pretty sure you can get organic versions too


Keep in mind the PH of potassium silicate, the common version in grow stores, has a extremely high PH and should be added and used with caution.


Thanks for the tip Matt.  I wonder if diatomaceous earth (which I've heard is high in silica) would work, or would it be detrimental to the system?
Silica in general has a very poor bio availability due to its ultra low solubility. Most soil has a large percent of silica in the sand portion, however it is insoluble and useless to plants and animals. Only a small amount each year can be made bio available by bacteria. I would only use a silica based gardening product for the desired effects. Also I think diatomaceous earth comes in many different grades depending on what percent of crystalline silica it contains some contain only 1%.

Drats!  Just found my first suicide.  The little bugger jumped out, and I found him dead on the floor covered in ants.

I've only lost 2 so far... guess I'm doing something right ;-) 

Well, nothing goes to waste here... the raccoons love dead fish!

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