Backyard Aquaponics
A place to discuss aquaponics

AA - I have a hanfull of shell grit in a bag hanging in my aquarium now. Do you think this will help? How long might it take? Should I put more in? Is there anything else I can do that would be quicke?

The shells are great, they just take a while. Potassium bicarbonate will increase pH and KH, potassium hydroxide will increase only pH without adding salts (bicarb).

So potassium hydroxide doesn't increase KH - what is in potasium bicarb that increases the ph. I may be reading the response incorrectly, because I thought it was the sdium that was the issue in sodium bicarbonate (ie salts) and therefore potasium bicarbonate would not have the salt issue. BTW where does one get potasium bicarbonate and potassium hydroxide?

VB, from the usefulinfo section;



A base like potassium hydroxide (or sodium hydroxide, AKA casutic soda) will raise ph.

A buffer like sodium bi-carbonate will raise ph up to an equilibrium point of 8.4 (i think), no matter how much more you dissolve or put into the solution, but it has a very strong buffering capability, in that it has the ability to "soak up" a large quantity of acid. There are complex equilibrium reactions that take place between calcium carbonate, dissolved CO2 and PH in an aquarium........if any one is interested let me know and i'll post an indepth (i warned you) summary in the useful info section.

But the simplest way to get your head around it is the way AA said,

A base (alkali) will raise only ph, and it will start dropping down again as the byproducts of the nitrifying process enter the water.

An Alkaline buffer will raise the ph, but also keep it there for much longer.

The good thing with shell grit and basically any calcium carbonate rock is that it has a very low solubility in water, so it will react only as the dissolved caco3 is used up. I will look up the equilibrium PH for calcium carbonate for you VB.

Buffers are non neutral "salts" of acids or bases, i think they are less acidic or alkaline than their parent acids or bases (PH wise), but have this "Buffering" capability.

PS guys, i'm not a chemical engineer, so if i slip up on one or two thing don't crucify me I just like helping people understand "concepts"
Steve

I think I wrote that badly VB. I was referring to bicarbonate of soda (baking soda) when I mentioned salts.

Calcium carbonate is excellent for water buffering as Steve rightly points out. I believe your water is swinging rapidly due to a lack of KH, carbonate hardness, so shells will fix it, but not quickly.

The baking soda will help carbonate hardness, but is not a good solution if you have a system where you aren't doing frequent water changes. The salinity only decreases because of water changes, and will rise over time no matter how much evaporation and addbacks if you don't change water. A bit of baking soda is ok as has been shown, but who wants to change water all the time because of baking soda used to amend their water if they don't have to.

A fast fix without adding salt, but amending low KH, is potassium bicarbonate. Fast fixes are never great for aqua, but sometimes necessary.

Pre-amending top up water is always better than amending your system.

Here are some up to date pics of the little grow bed that sits over the outdoor pond. It is pretty much at capacity in terms of plant growth and is unlikely to be capable of removing the amount of nitrate it needs to. Getting by Murray bed finished is getting kinda urgent (still waiting on the welder thermostat from Cigweld).

The pond now has 10 largish silver perch and probably 6 or 7 jade perch fingerlings. The Jades are a reasonable size now, but look pretty small against the silvers.

Fish - bit hard to get good pics. Like the one with the perch breaking the surface.

VB, you have some great pics there. Obviously, your perch and goldies live happlity together. Those grow beds are looking pretty thick. Some solid growth there yaar!

Yeh - I reckon 1 day the perch might just decide to eat the goldies. Not sure how many goldies I have left, I lost several to the filter (that was before I coverred it with a aeroponics basket).

Yes the growth is good. I have not been harvesting as I need all the plant matter I can to try and pull out the nitrates. I have thieved a couple of leaves off the lettuce and kale, and they tasted great. Ate the kale straight off the plant, delicious. Definitelly something I am going to grow more of in my full sized beds. This grow-bed is not draining properly anymore due to roots. The container is actually full of water pretty much to the top of the gravel. I am basically running DWC with gravel. I will fix the drainage on weekend by installing a larger drain, but when the water drains out the plants may have problems surviving. I remember AA saying that air roots can turn into water roots (which mine have had to do) but water roots can't turn into air roots (which is what they will have to do once I have the drainage working again).

howlong before those perchies end up as dinner VB?

If I get the proper bed going soon and therefore can start a proper feeding regime, I reckon they will be Xmas lunch. Give me the opportunity to show the family that what I am doing has outputs. Of course will have heaps of salad by then too. Jades will be ready by Easter I reckon.

Just got motivated and tested ammonia and PH again

PH is now 6.9 and surprise surprise the ammonia that was 4+PPM when the PH was 6.0 is now 0.25PPM!

I love nature.

I have said before that i like to keep the water betwwen 7.5 and 7.0 during cycling as this give the bacteria the best chance of setting up quickly, but once your system is established 7.0 would be the goal i reckon. It stikes a nice balance between mineral availability for the plants, bacterial function and fish health.

Tested ph in my aquarium, it is 7, so looks like cleaning the filter and/or adding the ph up has had the desired result. Tested the pond and it is now 5 - so I now have to look at fixing that. I have my other pond full of aged water ready to use in the one with fish in it. Luckily I checked the ph of that because it is 9 . Could this be because of algae - it is quite green because it has not had shade - remember this one has no fish in it at all and my tap water is only 7/7.5. Should I do a small 20% change using this water that is 9ph - or should I get rid of this and start fresh with some new water from tap (neutralised of course). If using the pond water, I run it through a fine knit fabric so I am not transferring any big pits of algae to the fishpond.

I'd go the pond water. sure to be a variety of life in it. But wait for other peoples opinions

Thanks Steve.

Bit the bullet and did a 30 or so percent water change using the water in the other pond. Added salt as I am still trying to get rid of the last of the fungus.

This morning I put a bigger drain on the little grow bed, which has solved the flooding problem. It will be interesting to see if the plants are okay, given that all their roots have been submersed for at least a week before today.

I also finished my grow-bed stand. Was able to use the welder by positioning the faulty element away from the heat source and trying to trust myself not to weld for too long. My welds were pretty dodgy, but they should hold okay.

Tonight I gave the stand its first coat of brush on cold gal. If I have time (which is unlikely) I will give it it's second and final coat tomorrow.

I went to buy a fire nozzel for my fire hose today (the one I have on it is the single stream type and I want one that will spread more), but the bloody shop had closed at 12noon. I will get it when I can and then grab a hald cubic meter of the 10mm drainage gravel in the box trailer and use the fire hose & ute (or in my case box trailer) method of washing the gravel. Will still be a few weeks before I am in action, because the next couple of weekends are writeoffs .