Backyard Aquaponics
A place to discuss aquaponics

G'day readers

ok we have a cycled system here with pea gravel, 8 gold fish, 30 trout fingerlings (thanks to the Troutman who delivered them last Friday).

Ammonia yesterday was 0. I checked this first because the new trout weren't feeding. Troutman advised running the pump constantly because our air pump gave up the ghost recently. I have also only recently covered the tank with shade cloth so the water is not very clear.

Either my PH kit is faulty or the water really is 8.0 on the ph scale. I did the nitrites and nitrates tests, one was zilch and the other was a trace but I can't remember which was which *insert blonde moment here*.

I bought a new air pump today so that is going, and added a bit of "ph down" that a friend offered... he said it should make a difference so I'll check the levels again in the morning.

What I'm looking for is a more permanent solution -- our tap water sits between 7-8 PH. My understanding is the trout need PH around 5-6. What should I add to the system ?????? when I searched through the forum (unfortunately the search engine removes the letters PH from the search) I found some discussions....



but still have no idea what to use for my system

Forgot to add the system dimensions:

1000L BYAP tank
600L of half blue barrels
pea gravel.

system has been running with the BYAP tank since February. gradually bringing more growbeds on line as hubby is FIFO.

thanks for your help

hey japris..

i also had major issues with ph... mine was sitting around 8.2 for months.. tank water was 8 and town water "procured" from a local park was 8.5..

i tried hcl, vinegar lemon juice... but still couldnt get it down for long...

but what i did discover was that some of my drainage gravel in a cup of rain water would raise the ph from 6.2 to 8 overnight...

so armed with deep and many pockets.. i mused around the local sand and gravel place and took a few samples of different gravels...one in particular dropped the ph of the tank water..so i put in 1 new growbed with just this gravel...and it has taken a few months..but the whole system sits on 6.2...

this worked for me... others say just to wait and let the fish wastes reduce the ph naturally..

good luck!!

If your system pH is high because of the media in your system (like if it has limestone in it) adding pH down will only result in pH bouncing which is not good for fish, bacteria or plants.

You might take some of your source water in a bucket with an air stone and test the pH when you first draw the water, then leave it to bubble overnight and test again to see what the water will naturally settle at. Then try adding some pH down to that water in a measured quantity then let it bubble again for a while before testing the pH. Then leave it to bubble over night again to see if the pH is going to rebound or bounce on you. This would be important information to know before you go dumping pH adjusting substances into a system with currently living fish.

The faster you try to move your pH, the more likely you are to cause bouncing or simply to hurt the fish in the first place. It is generally not the fish who suffer for the high pH except for when there is ammonia present. It is usually the plants that suffer most with a pH above 7. Be careful with lowering pH too much as the test kits often only read down to 6 and if the pH drops too much below that, the bacteria and bio-filter can crash and you can't even tell what the pH actually is.

With time and cycling the pH can come down provided the media isn't buffering it.

planted aquarium safe ph buffer : www.aquariumguys.com/acidbuffer2.html


hope this helps a little

I tried lemon juice but it had little effect over 24hrs. So I just got lazy and let nature take its course and now things are slightly acidic. Result.
But my grow media is pH neutral. I like a lost hippy's approach. Could be the way to go.

My Ph goes from 6.5 to 8.5 at different times of the year and have given up worrying about it, doesn't seem to bother any thing, have had shell grit in for a few months and has buffered pH, after adding fish you're amm and nitrates will probably go up but not for long, if fish are happy don't do a thing and levels will drop, I leave putting trout in as a late as possible as the colder the temp the better if you have amm spikes, fish can tolerate higher levels in colder weather, if you have marron or yabbies they prefer a pH of around 7.5-8.2

Seachem Acid Buffer is essentially the same as other ph-down products... main ingredient Sulphuric Acid (H2SO4)....

Pool acids are essentially the same... usually Sodium Thiosulphate... which becomes Sulphuric acid...

A lot of pool acids are actually "muriatic" acid.... Hydrochloric Acid (HCl).....

Adding acid to your system will move pH... but as TCL points out... if your water is highly buffered.... the pH will just keep bouncing back...

Until... you've dosed often enough to have used the buffering capacity up.... if however you're using the same highly buffered source water for top-ups... you'll continually be adding pH buffering back to your system...

It's often better to dose the source "top-up" water with acid to adjust the pH... rather than the tank itself.... although both may need to be done initially...

Your pH will drop as the system matures...

THANK YOU all for your help and advice...



this is my favourite method so far...

this afternoon the trout and the 8 included goldfish were hungry, although I only gave less than a tablespoon of food altogether.
I hadn't seen the trout feed much since Friday, thus my distressed call for help with the PH.

ammonia still 0.
nitrite is 0.
- husband says this is good because we now have the right bacteria to turn stuff into nitrates....

nitrate is 25mg/L

PH is slightly lower today. my test kit is a bit of a mixed bundle I think I need one that measures a bit more accurately. I get an 8 or a 7 colour !! nothing in between.

how do you find rain water affects your system ???

let's say I was going to add some shell grit... how much is a safe trial amount... ie, one bucket load or 100L ??? is that the same shell grit you get from the pet store for :

my assumption is that when fish are happy they will feed. correct ???

at what level nitrates should the alarms be going off to rescue the fish or change the water LOL

shell grit will raise your ph..

if your gb media is neutral... then patience is the best advice imho.. in my system the gb media was alkaline..so i had to intervene..

nitrates are what the plants use... if you have too higher levels...plant more...

high nitrite levels are the ones to watch... personally i have had no problems with nitrites...but there is always the topic search to get advice..

thank you.

Shellgrit is a self-regulating buffer.... it will only "dissolve" when pH is between 6.8-7.2... then it has released sufficient buffer... and won't begin dissolving again until that "buffer" has been depleted, allowing pH to acidify... and the grit to begin dissolving again..


All the research I've seen, or been able to access... suggests that the lowest level of concern for nitrates is about 400-450ppm... for the US Bluegill.... most other fish seem to be able to tolerate values beyond 500... at least for some time....

In an aquaponics system where the plants are taking up available nitrates... it would be unusual to see values beyond 20-50 (the latter when just cycled/planting)... and I've only ever heard of values above 100 a couple of times... for specific reasons...

In general... don't worry about nitrates... just plant more plants...

thank you again. as you can see fish are not my strong point
ha ha

I'm much better at training dogs and teaching music

so rupe shell grit seems like a great add all to any system to solve most pH problems?