Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

Michael asked me to start a thread about my experience using Maxicrop during cycling, and I'm happy to oblige!  Maxicrop is a liquid seaweed extract that you can also get in a soluable powder form. Using seaweed extract is talked about quite a bit on the Australian forums, but they use a different brand. the purpose for using it is to give your plants food before the nitrates kick in.  Good plant food that is not harmful to the fish.

When I used it last September I actually had a one quart bottle for my 300 gallon tank (probably only filled to 200 gallons).  I couldn't find any instructions for using Maxicrop for cycling, and according to the dilution instructions on the bottle I was going to create a very dilute solution using the entire bottle...so I dumped the entire thing in.  Turned the water brown for a couple weeks, but my plants were perfectly happy and seemed to have no ill effect on the fish.  

There is also a form with iron, but I avoid that.  I'm super hesitant about adding anything but fish food and the pure liquid seaweed into my system. I'm just not enough of a chemist to feel comfortable with measuring iron additions to the system, and haven't seemed to need any.  This fear has served me well so far.

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hum, I had thought it was organic but researching now, only the wettable powder is counted as ORMI listed while the liquid apparently is not (not sure if that is a change lately, the labels have changed so perhaps it is.)
Yeah, that's what I found, too.

TCLynx said:
hum, I had thought it was organic but researching now, only the wettable powder is counted as ORMI listed while the liquid apparently is not (not sure if that is a change lately, the labels have changed so perhaps it is.)

still fish safe but not ORMI.

Guess I'll have to start burning enough wood for ashes to adjust pH and get potassium if I want to claim "organic" and avoid the extra nitrogen from the powder.

This was the response from Maxicrop, "No. It’s the Iron , and the preservative used . "

 

Any other ideas for an organic substitute for nutrient deficiencies and a foliar for pests?

 

What about adjusting pH? I've heard that marble chips effect it.  It would be easy to drop a few in the fish tank (or sump if you had one).  Does anyone know if this really works and how much is needed to move the pH, say .5 per 100 gallons?

 

TCLynx said:

still fish safe but not ORMI.

Guess I'll have to start burning enough wood for ashes to adjust pH and get potassium if I want to claim "organic" and avoid the extra nitrogen from the powder.

Well the other liquid maxicrop is also not ORMI listed either.

 

A good Worm casting tea for foliar spray to combat pests and help against some deficiencies might work.

 

Adjusting pH, well what is your pH what way do you need to adjust it? 

Marble chips or limestone chips will raise the pH and add lots of calcium to the water as they dissolve.

I was thinking ashes since they will raise pH and provide potassium.

 

See the big aquaponic operations alternate between calcium hydroxide and potassium hydroxide to keep pH up and provide calcium and potassium.  Both of those things are pretty caustic (potassium hydroxide is basically what used to be used as lye and could be made by leaching wood ashes) so one must be careful when handling them as they can raise pH too much too fast and they are but dangerous enough to cause chemical burns to the skin if spilled when mixing.

 

However, if you are not aiming to get organic certification, I wouldn't worry too much about using the seaweed extract, it is definitely fish safe and Aquaponics safe.

The pH in my small (40 gallon) VERY new (<2weeks) tank is approaching 8.0. I don't understand as I've used the same city water in my 100 gallon tank which was 6.8 from the very beginning. I've been using some water from the established garden to help build bacteria plus a dose of ammonia and we've recently had some crazy rain storms. Figured it wouldn't be an issue. Will fish bring it down a bit once they go in?

In terms of getting an Organic Cert, I'm not really going that far. I was just hoping there was something out there, easy to get and use, that's OR certified to keep it all, well, organic...

How do you add ash and how much?




TCLynx said:

Well the other liquid maxicrop is also not ORMI listed either.

 

A good Worm casting tea for foliar spray to combat pests and help against some deficiencies might work.

 

Adjusting pH, well what is your pH what way do you need to adjust it? 

Marble chips or limestone chips will raise the pH and add lots of calcium to the water as they dissolve.

I was thinking ashes since they will raise pH and provide potassium.

 

See the big aquaponic operations alternate between calcium hydroxide and potassium hydroxide to keep pH up and provide calcium and potassium.  Both of those things are pretty caustic (potassium hydroxide is basically what used to be used as lye and could be made by leaching wood ashes) so one must be careful when handling them as they can raise pH too much too fast and they are but dangerous enough to cause chemical burns to the skin if spilled when mixing.

 

However, if you are not aiming to get organic certification, I wouldn't worry too much about using the seaweed extract, it is definitely fish safe and Aquaponics safe.

Here is some info about tap water.  If you test the tap water pH right out of the pipes, you are seeing a false low reading from trapped dissolved CO2.  Once the CO2 is allowed to air out much the same way you might bubble out chlorine, you will get a more true pH reading that may well be up closer to 8.

 

The bacterial action of the nitrogen cycle will naturally lower pH over time as long as there isn't too much buffer material in the system (if you use limestone, marble, concrete or shells as media, the pH will probably be stuck too high though.)

 

The fish providing the ammonia and thus making the bio-filter work harder could in that manner be said to lower the pH but the fish don't actually change the pH themselves.

 

I wouldn't worry about a pH of 8 right now I would say just do the fishless cycling and see if it comes down.  (That is assuming your media isn't causing the high pH.)

 

Collect some rain water for top ups to reduce the amount of hard water you are adding to allow the pH to come down a bit easier.

 

How to use ashes to keep pH up and provide potassium.  Well I haven't personally gotten to try it yet.  What I was thinking about trying was get some cooled ashes and put them in a paint strainer bag, dip paint strainer bag in sump tank.  Wait a bit and check pH to see how much/how fast the effect is.  Experiment with how much ashes and how long to let them soak to see what dosage is appropriate for the system.  (Might run this experiment with a 5 gallon bucket and system water just to get a baseline before actually doing it in a system.)  Ashes will raise pH and it is possible to over do it seeing as soaking ashes and then straining the water is how you make old fashion lye.

 

 

 

If ashes will raise PH that it's likely that this is all I will ever use.   It's amazing what tidbits you pick up here and there.

thanks

G

Guess I'll have to start burning enough wood for ashes to adjust pH and get potassium if I want to claim "organic" and avoid the extra nitrogen from the powder.

Keep in mind that soaking or leaching wood ashes is how old fashion lye was made.  Essentially KOH, you have to be careful with it as it can be caustic.

 

I also don't think this is the be all end all of pH adjustment as water chemistry is way more complex than that.  If you were using rain water to top up your system you will need to alternate different buffering means to keep from depleting your water of calcium since the plants use that too but if you are using well water that is high in calcium carbonate then you might see issues with high pH and too much calcium.

TC, I don't know if I would do that experiment in my main tank or any system actually. What I might do is go ahead and make a buck of lye as described and after it has processed add a few drops to another bucket full of fish water and see how much you need to adjust, then calculate for your system. But then again your method might be proper application. The rest of the lye you can use to make soap or remove hair from your hogs.

 

I believe a piece of dried then re-hydrated fruit wood would eventually do the same thing.

Spot on Carey, It would probably be best to test the ashes or lye separately to figure out the dosage before actually using it in the system.

 

I'm not sure about the dried fruit wood.  I always thought use of wood in tanks was more likely to lower pH than raise it but I suppose it really depends on the type of wood.

plants in gardens are being supplemented with kelp meal in the planting holes . the mineral break-up is the same as the ocean [ and you blood ] ; I actually feed it to my hens 1-2 % btw 

 

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