Backyard Aquaponics
A place to discuss aquaponics

Hey folks, after some recommendations if I could, 1000L fish tank with one soon to be two 500L grow beds, have been running my system fishless for about 2 weeks now, plants are growing great using seasol.
I would like to start getting some fish going to really get the system cycling but weather here in perth is all over the place, its spring but we are going from temps of 15 deg c to about 24 degrees c. The water in the fish tank is a constant 14 deg C. I was going to go and get some goldfish tio kick start the system, but the local stores to me want 6 plus dollars per goldie and they are like 20mm in length.

Would love to do barra but the weather is too cold, trout I believe are ending there season over yhere as well. Any suggestions

Thanks

hey simso, you could still go with trout for a couple of months, but price is about $5 or so, price of Goldies is a joke down here as well, Barra will be ok in another month but they are expensive to get at a reasonable size to grow out before april, for me barra season will be too short here, (hope monya isn't around ) looks like for me getting some Silver Perch and hope they grow before trout season starts

Simso, what are your water tests readings now?

IMO, I would say continue your fishless cycling with humonia and then get barra when the weather warms up..

Ditto... silver perch are your only other realistic choice... and they're an 18 month grow out

Hey mate, its only been going for 2 weeks, so I dont expect much yet, Ideally I would like to get the barras happening, when I go out I always order fresh water barras if there on the menu over anything else, including steak chicken whatever

Following readings so far, taken today, using the API freshwater test kit, so theres a bit of a guesstimation happening

Amm Over 2
Nitrite dead 0
Nitrate Over 0 But not by much
Ph 8.7 (used my digital test unit)
EC .07 (used my digital test unit)

Been told the Ph will drop down as soon as the system really cycles itself, so I havent added anything to try and bring it down, shame because Im sure the plants would like me to drop it down by a good 2 points, not the ideal situation

Natural is the best way simso, you may be 3-4 weeks off cycling fully, by then you should be able to put barra in, a guy who grew them commercially south of here said they will live in 14-16c but wont eat or grow, he had his water at 26-27c constantly which wouldn't happen here, nor in perth I feel, silvers will take a while to grow, unless you can get them at 300+ gms which will cost though, I am tempted to try trout through summer, where my system is undercover, and Narrogin is a bit like Melbourne (better quality people though ) will be 40c one day and 20 the next so doubt my water will get above 22c

pH 8.7 Simso... are you sure... that's quite extreme... where are you getting your source water from??

Yeh its over 8 no problems out my way, been doing hydropnics for a while, and this is a common problem, I usually throw some lemon juice in to bring it down, but unsure whether to do that in the aquaponics setup, so have left it alone waiting for the system to cycle, because as Ive read most people have problems keeping the ph up with a cycled system. If people dont think lemon or lime juice will hurt, then Ill through half a litre in

Out our way know our local water is obtained from bores and then fluorided and chlorined, we have a bore here at home as well, and pure limestone underneath us, I filled the 1000L up with commercial water from our tap not our bore as well

While it's true your pH will probably come down once you're cycled and begin feeding your fish and nitrification commences in earnest... you will find it difficult to cycle your system up with your current pH... which will be inhibiting bacteria growth, almost killing it off...

In your situation, and as you don't have fish as yet... I'd be tempted to adjust the pH with "pool" acid.... hydrochloric acid... to assist your cycling....

Once running, top up with the "treated water" initially... until your ph drops.... then, as luck would have it... you limestone aquifer water could be used to buffer your pH when top ups are required and when your pH warrants it...

I think Nitrosomonas (bacteria that converts ammonia to nitrite) does not really like high pH. Did a wiki search.. between 6.0 to 9.0 pH, with optimal conditions slightly basic. Probably the same issue for the bacteria that converts nitrite to nitrate.

Since you don't have any fishes yet, yeah, lemon juice should be okay. I think some people have used pH Down from the local aquarium shops...

Cool, I just dropped in 250mls of lime juice, gave it a stir and let it settle for an hour Ph is down to 7.8, will check it again tommorrow night and if its still the same, will drop in another 250mls and bring it down to low 7's

IMO, 7.8 is good enough...

You'll need a truck load of lemons.... buy a bottle/container of "Diggers" Hydrochloric Acid from Bunnings...

If you going to do it... then moving to 7.8 is a bit like throwing a snowball into a fire...

Bring it back to 7.0-7.2... minimum

P.S ... check your test... IMO... there's no way 250ml of lemon juice would have moved your pH from 8.7 - 7.8 ...

Unless your pH was more like 8.0-8.2 (max) in the first place...

Lemon and lime juice are really good for dropping Ph, have been using them for hydroponics for many years, for 10 litres I use about 20-30mls to drop a full point, you buy it by the bottle not by the lemon / lime

As far as dropping the 1000L with 250mls, will wait until tommorrow night to know the true value, and then adjust if necessary, will let you know the value. PS yep it was ph 8.7 to start with