I am well into the process of setting up an Amazon/South American system. I have a 48 x 24 x 30 inch tall tank. I am running a 40 gallon sump that will be illuminated opposite the main tank (evenings), that is planted.


I have wood in the main tank with a complex substrate. The sump is compartmentalized with an inflow tower that drains out through pumice, into a main plant growing area and through baffles containing activated carbon and peat to a MagDrive 950 GPM. The major flow goes through a UV unit that runs in the evening. Part of the flow is diverted to a CO2 reactor (an old O3 reactor), that rejoins the flow up into the main tank. Because the pressurized CO2 system will be on all of the time to feed the sump plants, I have added an airstone in the baffle before the MagDrive compartment. Hoping to add a bit more DO. Currently the drop checker indicates green.

The main tank has two inlet flows. The flow from the bottom is a drip irrigation line with 25 outlets pointing upward. The other part of the flow is diverted into a "lockline" fan that is at the surface. The flow does not break the water, but ripples the surface.

The light wattage on the sump is about 1.7 W/G and the deep main tank has about 4.3 W/G. I have vals, swords, ludwigia, cabomba, plus others plants in both the main and sump. The plan is to have a black water South American community system. I am planning on warm water livestock, where discus may be in the tank, but a community system is my goal. I have started to fertilize with Flourish and Leaf Zone at fractions of the suggested rate spread out over a week. I have KNO3, KH2PO4, and CSM+B on the way.

My system water parameters are currently as follows:

pH 7 - 6.8, KH 3*, GH 8*. I have been mixing RO and city water. RO water parameters are pH 6.4, KH 1* or less and GH 1* or less. Here in Las Vegas the water is HARD: KH about 10*, GH about 22* (these numbers are a bit more than published, but not much (GH 17*). Also, I am still getting used to reading all of the different colors in the test kits. I would like to get the aquarium temp at about 84*F, but it is creeping up into the 87* range. I would rather not have to purchase a chiller, but when the outside temp is 100* to 110*F, and I am cooling the inside to 84.The MagDrive adds heat, the Satellite Duals, the air pump all add heat and the temp rides up to 87*. I placed a fan in the aquarium stand to pull hot air out but still the heat is up. I can cool down the house to 78* or buy a chiller!

Questions:

Do I need to draw the pH down to 6.5 or is 6.8-7.0 good enough with the CO2?

Any suggestions for keeping the water cooler?

- - - - - - - - - Thanks for this community network - what a great resource!

Regards,
Joseph

Adding a night time source of plant growth is not needed.
And it requires CO2 additions.
Use the main tank for this and keep them on the same timer.


You seem to have many things going on here in effort to cover every base.
You do not need to do that.

I'd suggest more flow, say another canister filter, 350-500gph.



I think having two opposing things going on is not the best approach, don't you?
If you want more O2, go buy an O2 cylinder at the welding shop, get a O2 reg and needle valve and bubble more O2 pure into the tank at about 1 bubble a second.
Good surface movement will also help prevent low O2.


So why the concern about O2?


You have too much light if you want to know the truth, try about 1/2 this amount.
It works very well and is much more stable. You have lots of fast growers, you are going to have to work to keep up with that at that light intensity when things are really healthy.



Tank water is fine there, temp is as well, it's not a big deal if the summer creeps up higher, adding a fan clip on for the surface will help cool about 2-3F.
Sometimes you can find those cheap Carboy Water coolers for 20-30$ and take the chillers out of those and drop the probe into the sump to drop the temp down a few degrees, (maybe 5F or so.)

Stop thinking about pH, think about CO2(KH+pH).
CO2 is the concern, not a specific pH.


A pH target for that KH is found here assuming that the KH is all from bicarbonate
DFW Aquatic Plant Club--KH-pH Table

So about 6.4 pH is the target.
So you keep adding CO2 until you have a pH of 6.4.

But..............you are using peat and who knows what in the substrate............so that target is likely lower than that, perhaps 6.0, hard to say depending on when and how much peat is added, or what all is leaching out of the sediment.

And what is left in the tap.
All those things can affect pH.............and they artificially lower pH fooling you into believing you have more CO2 than you do based on the chart.

I'd remove the peat personally and leave it out from here on.
You soften the water with RO already, no need to do more.

regards,
Tom Barr

I think it is probably fun to build up such an elaborate system, trying to mimic a natural system in a specific river area. If the goal is just enjoyment, and that is certainly a worthwhile goal, then people who enjoy doing that should do so. But, growing a variety of plants in a tank of water that will also support fish very well, really doesn't require that complexity. We all need to understand our goals and do what fits those goals. That's why this is a hobby and not a profession.

I now understand that the plants will add O2 to the system more efficiently than an airstone. As I reviewed, I also realize that higher flow is another key to "DO" success. I have no canister filters on this set-up, I have a 950gph pump. I could easily add a bigger pump."




Thanks for these suggestions - the house was at 78F all day. The system cooled to about 85F maybe a bit more on the marrow.




Question: When my drop checker, filled with water from my system, is green is it giving me a valid reading?




I can take out the peat - I was going for the dark water look. The carbon seems to have absorbed most of this along with the tannins from the oak.




Hoppy gets close to the mark. I want to have some fun here. I have been growing terrestrial plants, mostly xerophytes, for over 4 decades. Some as a professional but mostly as a passion. I know that there are about as many ways to grow these plants as there are growers. From reading posts of marine and freshwater enthusiasts I realize that the "aquatic confines" may be a bit tighter, but there is room for experimentation.


Gentlemen thanks for you constructive comments. Regardless of the enthusiasm I may have for my ideas I realize that there are some basics that are different in aquatic systems.

Thanks,
Joseph

The drop checker is only a pH checker unless you use a standard KH solution in the bulb in place of tank water.