PAR and EI

450 at surface, 140 at the bottom.

I still run 150 at the surface, 50 or so at the sediment, and modify it to use ADA AS, then a richer PO4. NO3 typically at 15ppm-20ppm.

My ADA As is older now, so I add more NO3, prior, 5-10ppm was plenty.
Watching growth rates is pretty telling.

Regards,
Tom Barr

 

Hi,
I have a similar tank, 120 Gallon, 120 cm x 60cm x 60cm.
I use a Tek T5 fixture. 8x 54 W bulbs.
Typically, I use only 4 bulbs, so about 1.8w/gal and about the lower end of the light range listed, 120 surface/50 at the sediment).

If I'm feeling green and gardening if more interesting, the aquarium is fine, noi algae, I bump it up to the full 3.6W/gal.

I re started this tank after a move.
It did many/most of the issues you also have had.

I took inoculum of algae from this tank and tried to induce it in the other tanks with the same light/color temp/sediment/plant species etc etc.

Never could get GDA, and most other species to take.

Another tank had a simiklar but milder problem.
Both where overflow sump/wet/dry filters that had issues.

I changed the sump and sealed up the wet/dry.
I made a concerted effort to maintain the water level inside the sump/aquarium
I cleaned the over flow and sponge filters 1-2x a week.
I added a cansiter in post filter on the 120
I did not add any canister to the other problem tank(milder issue).
I started out with most rotten plants when I did my move in Aug.
I got the plants growing again pretty good.
I had many rare hard to find species, so I knew I would rather get algae and have some decent plant biomass, than letting the plants grow in a bit and possibly lose them. So I was impatient there, but I took advantage of it for another reason.
I did 2x a week water changes(could have done every other day).

I cleaned the CO2 disc every 2 weeks rather than 4(Bleach it with toilet bowl cleaner/add dechloro).
I focused much more on CO2.

Dosing was the same.
Sediment the same.
Lighting the same.

I did change the lighting later after a bout with Spirogyra. One algae that I'd only had some unconclusive success with. So wanted to test some ideas on this agressive green algae since I had the rare chance to work with a bloom stage. GDA has been far more difficult to work with.

So.........

My algae bloom had started and I had very nice plant growth, but very fast algae growth. The CO2 was also good. At least I thought.

Still, I had an algae issues with good plant growth. It was not the optimal growth I know and love, but it was pretty good nonetheless.

This makes for an interesting system.



I wanted to work with a light method to control algae, but different than the typical less or shorter day cycle. It was more like a "siesta" approach, but much longer.

Same idea though.

I do a 60-80% water change(algae often sporulate after a large environmental change) . Turn off CO2, do not add any ferts after etc(GH might be one if you want to keep the TDS up). Cover so that no light gets in, trash bag etc a few layers thick, wait 3 days, remove and do another change, add CO2 back and try and tweak it slowly.

Wait 2-3 days till you see the algae come back a little bit, then repeat the blackout again.

After 3-5 cycles of this, the CO2 is really good(observing it and adjusting it slowly after each blackout). The algae has been tweaked out and stressed a great deal, plants do fine with enough light every few days followed by 3 days of darkness.

You can keep on doing this as long as it takes.

Algae never over runs the tank while you are adjusting things!

I used the 1.8/w gal light during this time and then after I thought the algae was on the run, I left it on for 2 weeks and trimmed and removed any places that the algae seemed to catch and accumulate. The CO2 is well adjusted and over the last month, the tank has really bloomed out well, even though the CO2 is the same.

I would get issues if I did not do the water changes early in the day, not clean the filter, keep the CO2 in good clean shape, too much water level change, I also add a fair amount of flow(600 gph wet/dry, 250 Gal via a powerhead).

My overflow pipe degassed a lot more CO2 than I thought and the other 60 Gal has a better overflow that resulted in a less problematic algae issue.

The issue was multiple, even though the general bioinidicator was poor CO2.
While many will suggest "oh yes, it's a CO2 issue", and it many ways that is the root, the solution and causes are many.

I tend to take issues case by case, not general.

I think you can resolve the issues in your 120 Gal tank still yet.

Mostly via the blackouts/refocus on adjusting that CO2, providing good current(you lose more CO2, but can add more easily too) and better filtering/cleaning frequency to provide good high O2 for fish.
Change flow patterns around the aquarium etc.

Trim off some plants that do poorly, keep the tank clean, do water changes, 60-80% and do them after 1-2 hours after the lights are turned on.
This post water change planted tank is a good "reference", look at the aquarium good that night before the lights go off. That is the optimal. So you can do many water changes, maybe 2-3 a week to get the aquarium into better shape.

All this work/effort is required to get the tank to start growing plants well, without algae issues. Once you get there, it's MUCH easier.

Once you tip the scales, it's easy.
Try the blackouts, cleaning, and CO2.

Regards,
Tom Barr

 

Also, the light and CO2 are key to most everything, nutrients can be, but tend to be less effective at getting at the root and controlling algae to the same degree and generally are indirect in their effect(mostly on lowering CO2 demand).

Regards,
Tom Barr

 

The nature of the overflow pipe was using a CPR(60 cube) vs a a regularly stand pipe built in overflow box(120 Gal).

The CPR seems to reduce both noise and the degassing.
Easier to use and easier to clean. Takes up less space also, easier to hide/keep shrimp and fish out of or from being sucked into.

I can also remove the weir box for a picture.

I think most of the prefilter overflow hang on boxes work pretty well, I opted for the CPR, however, they stink for one reason, you need a continuous pump to remove any air in the siphon, otherwise the sump runs dry and the tank overfills and floods.

I use a tom's pump for that, so not a big issue, still, it could be an issue and it's another thing to go wrong, the other overflow boxes using a normal siphon do not have that issue(or nearly none).

They are also much quieter than the typical built in overflow section.

Huge issue for me.

Regards,
Tom Barr