Learning to Read a Graph (again)

[Philosophos]

So I looked at my aquarium today. The algae was pearling. The HC was too, but also the algae. Every number I could check and all the numbers for my dosing had been, as far as I could tell, perfect. Yes, even the CO2 was high enough. I decided to develop a nervous tic for a little while, and then forget about it because I had other things to do.

By sheer coincidence, I was checking spectrum graphs to a little emerged growth experimenting. I decided to pull out my sunpaq box, and take a look for comparison.

Ever read a graph by 100nm off? This is my second time doing it. It appears that Sunpaq's 6700/10,000k has a very, very large UVA spike/hump that almost seems to be at the same proportions to chlor a/b stimulating wavelengths as the sun. I was wondering why I had 5 different kinds of algae spread around the tank, despite plant growth being wonderful. I think I know why now.

I will be moving to a coralife 6700k bulb tomorrow, which has a small fraction of its lighting in the

 

[Tom Barr]

I do not think the spectrum will offer you much in the way of algae prevention vs plant growth.

They(algae and plants) use the same type of light to grow and both can adapt to a wide range.

Intensity is more likely to be an issue, then perhaps duration.
From there, it's an issue of nutrients/CO2.


Regards,
Tom Barr

 

[Philosophos]

I was under the impression that UVA light was something that inhibited plant growth, while algae and cyanobacteria could adapt more easily. I'll have to hit the books again and see if I can find a good study comparing the two.

Until then, I wouldn't mind your opinion on what you think I'm doing wrong. Here's the details, pics will be posted later on when the batteries are recharged:

Light:
65w about 4 inches over a 20g with no lid; as mentioned 6700/10,000k Sunpaq CF. Duration is 10 hours a day with a 2 hour mid-day break.

CO2:
Turns on a half hour before lights, stays on through the break. Drop checker is slightly green at lights on (10am) and yellow by noon. Bubble count is too fast to estimate. Light pearling throughout the day, heavier later on.

Ferts are and schedule are as follows:

Volume: ~65L with displacement.

Macro Solution: 35ml of standard EI ratios, minus MgSO4.
NO3: 19.5ppm
K+: 21.2ppm
PO4: 2.85ppm

MgSO4 Solution: 36ml (100g MgSO4.7H2O in 1L, ~10mg/ml Mg):
Mg: 6.9ppm

Micro:

Iron Solution: 36ml/wk. @ .05ppm Fe(III) (from 10% Fe(III) chelate)
Fe: ~0.28ppm

18ml Flourish

Schedule:

S: 30% water change. 12ml Macro 10ml MgSO4 solution
M: Micro 6ml Flourish 12ml Fe
T: Macro 6ml 8ml MgSO4
W: 30% water change. 12 ml Macro 10ml MgSO4 solution
T: Micro 6ml Flourish 12ml Fe
F: Macro 5ml 8ml MgSo4
S: Micro 6ml Flourish 12ml Fe

-Philosophos

 

[Philosophos]

Here are the pictures. They're a little late in coming; I was out for the weekend. I also bought a different brand of hood with exactly the same bulb. It seems to have a better spread and intensity.

Yes, that is algae growing on top of algae. Interestingly the drop checker has been turning greener since I left. I'll be addressing the CO2 issues. Could that alone do so much?

-Philosophos

 

[Carissa]

Is that real wood? I have had terrible issues with algae when I try to use driftwood. I think it must feed it in some way.

Are you doing gravel vacs with your water changes? Too much gunk in the substrate always gives me algae issues that won't go away.

 

[Philosophos]

It's all real; Malaysian and Mopani. Usually it needs a superficial scrub every few months, and the odd squirt of excel. This algae growth happened inside of one month. There's no competition for light on the driftwood, and yes, there's probably some nutrients too.

Gravel vac is an impossibility outside of light, superficial stuff. My fiance and I try to suck out detritus as much as possible, but the substrate is anaerobic at lower levels. Higher up, the root structures bring in their own oxygen. This is pretty much the only way I know of to treat substrate covered in HC and glosso.

-Philosophos

 

[Gerryd]

Hi,

Yes insufficient or unstable c02 levels can quickly show up.......

The algae on your wood is the same I get when c02 is off. When c02 is on, I don't ever clean the wood. C02 bad=manual scrubbing lol

 

[Tom Barr]

Gerry hit it.
Most of my tanks are loaded with wood.
No issues, when the CO2 is poor etc, I get algae, so I tweak it and add more, reduce light perhaps, Add excel, clean, do larger/more water changes, add excel on infested spots etc, do a large water change, say 70-80% to expose the wood to air and then dribble excel on it, then wait 5-10min, refill.



Regards,
Tom Barr

 

[Philosophos]

Ok, no doubt it's the CO2. I could almost watch both the plants and algae grow today, and the drop checker never went to full yellow. Not even turning up the CO2 and bringing the water line all the way up to decrease disturbance helped.
I will say 50 "It's the CO2"s counted on a rosary of needle valves.

Most of what was mentioned here was already in progress by the time I started reading. It's nice to know that my reasoning is getting better. Much of it is thanks to this site.

The water changes are something I definitely didn't think of. Is it for the sake of spores, nutrient balance or both? They will be every day for a few days. I've got a pair of apistos displaying to each other, and the water changes will be good for them, too. Unfortunately that also means I have to keep it to 30% until I figure out how to reduce their stress levels during larger changes. I've got a few ideas already.

Tom, you and your site have contributed to my knowledge of planted aquariums more than anyone else. The least I can do for now is get a membership.

-Philosophos