Newbie Questions

[keith_r]

the nitrification process will bring your ph down as your system matures

[Spooky__Fish]

Thanks for posting the chart, that displays what I have been reading.
Iron appears to be the biggest problem with high PH. My water is very high in iron and calcium, but despite the amount of iron, the chemistry may make it mostly unavailable to the plants.

Regardless of the facts, I'm going to experiment to see how practical results compare to theory. There are many successful things I do in aquaculture that are diametrically opposed to theory. I'm not afraid to attempt something that bucks convention. I figure if iron is a problem, chlorosis will be the response, and it will be very easy to diagnose. I also figure wrong a lot

I'm wondering if the calcium may be an issue? As it is, calcium precipitates out of the water and coats the ponds, tanks and filters. I'm thinking that if I drop the ph, the roots may turn into stalagmites?

the nitrification process will bring your ph down as your system matures

It would need to change it profoundly, I doubt that process would do more than drift the PH down slightly over time.
Regardless, I much rather use the high ph water I have, if I can.

[badflash]

Again, don't fight the water. The water will win. Find plants that like what you have to offer. Iron is easy. Add a little blood meal. Remember, you want to grow greans and reduce or eliminate water changes. If nothing else, toss the plants on the compost pile. You'll probably end up eating them. My peacocks eat the aquatic plants, so I need to separate them.

[urbanfarmer]

It would need to change it profoundly, I doubt that process would do more than drift the PH down slightly over time.

The pH "drifts" faster at higher pH than at lower pH. The pH "drifts" 1000x times faster at pH 9 than at ph 6.

2 NH3 (ammonia) + 3 O2 (elemental oxygen) ==> 2 NO2 (nitrite) + 2 H (hydrogen ions) + 2 H2O

In other words, for every mole of ammonia it will yield a mole of hydrogen ions. Therefore, 1 mole of ammonia in 1,000,000 Liters of water later and your pH will go from 7 to 6 (roughly). Translated, that means that for every 142 grams of food (assuming 30% of the protein in the feed converts to ammonia for 40% protein feed) per Liter will lower your pH 1 point from 7 to 6. 142 grams is not a lot of food in itself; so, multiply that by how many liters (multiply your gallons by 3.78) are in your system and that will give you how many grams of food until your pH drops by 1. This ASSUMES your fish EAT all the food. Food that does not get eaten will produce far more ammonia.

It's 12 pounds of food per 10 gallons of water (assuming you have the fish to process the feed). It does not matter if you feed the 12 pounds of food over 1 year or 1 month. The pH will drop to 6 after 12 pounds of feed converts to ammonia and then nitrite.

Interestingly, if your pH was 9 the same amount of feed would roughly change the pH to 6. I know, that might not make sense, but remember pH is a measure of the negative algorithm of the hydrogen ion concentration. My calculations above are for adding 1 mole per 1,000,000 liters; therefore the new pH is the sum of the previous hydrogen ion concentrations, which if coming from a HIGHER pH will always yield a little tiny bit less than a pH of 6.

This also means that if your pH is 8 or higher it will only take 1.2 pounds of feed per 10 gallons of water to lower your pH to 7. Now that's not a lot of feed at all!!!

At a general stocking density of 1 pound of fish per 5 gallons of water with a grow out of 6 months and a 1:1 ratio of food to grow to the stocking density, it would take about a year to go from a pH of 8 to 7. That simplifies the situation to having the fish NEVER grow. As we know, fish grow and require different feed at different stages of growth.

I'm not sure if I messed something up here, I just ran through all that as a personal exercise while listening to some very loud children... but, assuming I wasn't too far off, that should give you SOME idea because the pH is not linear whatsoever.

THE MORAL OF THE STORY: DON'T BOTHER CHANGING YOUR WATER.

MWAHAHAHAHAHAHAHAHAHA

[Spooky__Fish]

THE MORAL OF THE STORY: DON'T BOTHER CHANGING YOUR WATER.

I like the idea, but even if that's correct it still don't work for me. Remember, my metrics are much different from tilapia, I'm starting with tiny fish and growing to 2".
At my target density of 4 fish per gallon, were probably talking an average of .125Lbs./day for a 1,000gal pond. That's 0.00125Lbs./day/10gal or 0.456Lbs./year/10gal or 4.5Lbs./decade/10gal or 27 years till the 12 pound number is reached

Regardless, thank you for taking the time to compose such a cogent post. I'm so used to the inane droning on other sites, that I found your use of facts, mathematics and logic especially refreshing.

[badflash]

4 fish per gallon of that size is a pretty light bioload. I'm at around 1/4 pound per gallon in my system. I'm running peacocks as well as tilapia.

[keith_r]

my system was pretty steady at a ph of 7.6 to 7.8 at least into november, from late april or early may (the last time i tested the water was 11/6)
today the ph is at 6.4, maybe a little less
i've only been lightly feeding the new fish and the bigger ones have been eating lightly as well, amonia was at less than .25, nitrites were a little high at .5 and nitrates were at 40.. as an aside, i'm pretty happy with how 3 pairs of t8 lights are doing

[Spooky__Fish]

4 fish per gallon of that size is a pretty light bioload.

Yes it is.
Current load is 1.2 fish/gallon due to the limit of my current production. My goal is 2 fish/gallon, however with AP I'm thinking I can easily double that to 4 fish/gal and have better water quality. 4 fish/gallon would be a big win and make me very happy, once again...my metrics are very different from tilapia.

[Spooky__Fish]

Well my experiment failed.

I did a floating raft with mesclun mix.
All red leaf and light green varieties could not grow successfully.
Darker green leaf ones technically survived but did not produce anything that could be considered a crop. Clearly the nitrate consumption of barely living specimens is negligible.

I'm glad I did such a small scale test instead of investing in something production size. Looks like I can't do AP without changing the Ph of my water, and that ain't happening.

Thanks for all your help. Now I know you can't do AP with lettuce at Ph 8.5!

[urbanfarmer]

WOW Spooky__Fish, I AM SO SORRY NO ONE RESPONDED TO YOU SOONER.

I am 100% confident aquaponics can help you achieve what you are trying to achieve. There is NO reason why it wouldn't work if your only obstacle is a slightly high pH. Your pH is perfectly workable... One note on "fighting the ph" have you tried something cheap like hydrochloric acid? It's available at most pool or hardware stores for less than $5 a gallon... I did some quick math... and 1 gallon can EASILY take down 1000 gallons to 7 pH with well over half a bottle left over... let me double check that and get exact measurements for you tomorrow...

Well my experiment failed.

I did a floating raft with mesclun mix.
All red leaf and light green varieties could not grow successfully.
Darker green leaf ones technically survived but did not produce anything that could be considered a crop. Clearly the nitrate consumption of barely living specimens is negligible.

I'm glad I did such a small scale test instead of investing in something production size. Looks like I can't do AP without changing the Ph of my water, and that ain't happening.

Thanks for all your help. Now I know you can't do AP with lettuce at Ph 8.5!

The Master Gardeners have a saying: RIGHT PLANT RIGHT PLACE

I can tell you for a fact that there are plants that thrive at a pH of 8.5 (well according to the literature and testimony from many county residents).

More importantly, I have even read research for commercial applications where pH of 8 was used and no difference was determined in yield from the supposedly better lower pH of 6 (please note my use of 1 significant figure as I do not recall the decimal place of the numbers).

I will post a little more tomorrow, but please please do not give up hope! I think most of us here are reading this thread and thinking WHY DIDN'T IT WORK!!! Tell me a little more about what happened in the meantime, but there is NO reason why this shouldn't work!!!