Help for FW Newb w/ Planted/Cichlid

[cowman345]

My goal is a 75gal Mbuna Cichlid Tank that is moderately to heavily planted with CO2 injection.

I realize this is unconventional... I've been inspired by and the folks over at that site. I'm fascinated by creating a viable "fish garden" by creating a unique, but efficient (and guided/manipulated) ecosystem. To start, I'm basing my design off the one at this link.

I really need help, I'm a bit lost. I'm 2 months from my bio degree with a minor in chemistry already completed. I've read several articles on CO2 injection and I pretty much get it, but I have several questions. First, here's some stats:

* 75gal standard aquarium.
* 4 VHO (10000k, actinic, 2 NOs on overdrive for 360 WPG).
* 1 Filstar XP3 to start.
* EcoComplete and Cichlid Sand mix for substrate
* Lava Rock for cichlids

1. Substrate: How much buffering (cichlid sand) substrate and how much Eco-complete should I use? (I'm used to doing deep sand beds for reef tanks.)

2. I assume I should get an idea of pH/KH/CO2 requirements AFTER setting down substrate, then go for a target of perhaps 15ppm CO2 initially before I add plants. (no fish yet). Am I on track here?

3. Does target dissolved CO2 level increase with increased plant mass? Or is simply more CO2 injected to maintain target level?


Well that's a good start, I guess... don't even want to worry about fertilization quite yet. Any advice or assistance would be greatly appreciated! This is my FIRST freshwater tank, I'm an experienced reef aquarist, and feel I can really make this work, but need a helping hand to get off the ground here. THANKS!!

-dave-



this magnificent tank

 

[happychem]

If you're an experienced reefer, you can definitely get this to work. Many of the same principles apply.

Scratch the actinic bulbs unless you just like the colour. They're good for recreating the light levels 10+ m down in the ocean, but that's not FW plants. Some folks claim that they'll induce algae, I'm not sold on that, but I'm also not convinced (as some others have claimed) that they're of any benefit either. 10000K is on the blue end, my personal preference is 6500K, but as I said, it's personal and 10000K will do fine.

You may be going a little overboard on the lights. That's close to 5 wpg, which is pretty heavy. If you were to aim around 3 wpg, you'll have a much easier time with nutrient control and algae prevention/elimination.

1. A 50/50 mix would be fine, and a good place to start. Have about a 3" deep layer, 4" if you don't mind losing a little tank space, it'll make the planting easier.

2. Your ideal pH - based on CO2 target levels - will change depending on your KH, which will increase with time. CO2 will speed the rate of increase by increasing the dissolution of CaCO3 (CO2 reacts with CO3 and water to make HCO3). So for the first month or so you'll need to be on top of your testing to get your CO2 levels down. But after you get a handle on it you'll know the input rate that will provide you with a good level of CO2 for your setup.

Your target CO2 level - especially with that amount of light - should be 25-30 ppm.

Get CO2 up, add the plants. Before you add the fish don't be shy to crank the CO2 up to 40-50 ppm. It won't hurt them and it will ensure maximum growth rate for getting the plants settled in. After a few weeks, once you notice that the plants are thriving, then start adding the fish a few each week, remember to drop the CO2 level (if you increased it) back to 25-30 ppm.

If you've got the money to spend on a solenoid system, do so. Then you can hook the solenoid up to a timer to shut off the gas flow at night. This will save you gas and give you the security of not building up harmful levels of CO2 overnight.

3. Target level remains constant. Input must balance uptake to maintain the level, ergo, more plants = more uptake = more input

Good luck and post some pics when you've got it all put together. I'm really interested to see what you do with it.

 

[cowman345]

Thanks for the well-worded and easy-to-digest reply!

One thing I'm concerned about... I have read in many places that CO2 levels above 25ppm will be harmful to fish... is this not true?

Also, about lights, perhaps I'll run a 10000k and a 50/50 bulb for total of 180W.

-dave-

 

[happychem]

Fish will be fine at CO2 levels between 25 to 30 ppm.

I've had my CO2 up around 50 ppm for a short period of time without any aparent distress (no gasping at the surface). It wasn't on purpose, mind you, nor would I recomend 50 ppm as a target, I think that I was lucky. It was just a problem with my DIY setup, rather a particularly warm day and a fresh batch of sugar mix. I only offer it as empirical evidence that 25-30 ppm is fine.

In the end, intensity of light is more important than spectrum (IMO). I've grown plants very successfully with a cheap halogen desk lamp on a 10 gallon tank. Halogens are pretty orange in comparison with "proper spectrum" fluorecents. Besides, people grew plants for a long time with incandecent bulbs. Certainly adding to the blue end of the spectrum will do no harm, so if you like the look of it, do it.