Journal Experiment Tank || 90x50x36cm, 39gal, Horizontal Reactor High-energy Aquascape Journal

[Kwyet]

How heartbreaking!

 

[Naturescapes_Rocco]

Day 173-184: Deep clean, Replanting, and a few new plants!​

I removed a lot of the old plants, did an insane 5 hour deep clean using my not-yet-trademarked Aqua Vacuum setup, which allows you to siphon all waste and detritus while recycling the water in your tank!... All it is is a Netlea Prefilter with a fine reuseable sponge and an inline pump, with temporary lily pipe return and acrylic tube intake. Someday I'll post it, because it's awesome.

After a deep deep clean, I removed plants and prepared them for replanting, trimming basically any damaged, algae-covered, or unhealthy leaves.

Then I let it grow out for 11 days again:

Ta-daa! Now with plant names:






Spot dosing the Crypt parva with H2O2 has helped get the algae under control. Limnophila aromatica mini continues to grow horizontally more than vertically in high light. Really more of a mid-background plant than a true background plant, even in this shallow tank...




The Lobelia cardinalis mini from @Burr740 is awesome. I get it now. I avoided this plant for years for some reason, but it's super bushy, easy to trim, grows very short and rounded. Great plant!

Next to it is Piptospatha ridleyi:

Not much is really posted about this plant online. Many say it's not even aquatic. In fact, one of the only instances I can find online of this plant growing submerged is from this thread from Burr:

We'll see if it grows well (or if I like it at all!). It's not a very "natural" plant IMO, but then again, not many in this tank look like they are anyway...


Pearling is back in full "upside-down rain" status again. Lights are about 150-170 PAR at the substrate, closer to 300PAR at the surface (measured using Photone app and cosine diffuser with iPhone 15 Pro in a ziploc bag).



I really like how this left side is coming along. I think I'll need a different/taller plant for the main background bush to replace the L aromatica mini. It's just too horizontal, but would make a great plant in the midground somewhere! Also totally in love with Bacopa colorata. There is nothing like that beautiful salmon coloration, large stems, and tulip-shaped leaves. I'll have that in every colorful tank for sure.

Let me know if you have any questions!

 

[techman81]

So this was all just intended to test our faith in you?

 

[TRyan]

@Naturescapes_Rocco I really enjoy following along on your journey. You are excellent at creating an amazing journal! So thorough and well documented, great photos... An inspiration!

I'm curious about your Brooks flow meter. I have the Dwyer and mine jumps all over the place if I even look at it wrong. Would you happen to have a link as to where you bought it? Are you still happy with it? I don't have a sweet betta tail regulator, only CO2Art Pro SE. Not sure if I would need a better one for more reliable fine tuning?

Thank you for all of you helpful content!

 

[TRyan]

Warning: fertilizer ramblings. Skip if you don't care about numbers!

A few weeks of 30-9-39 and I'm hooked, maybe for life. 70% Water changes, with 20-6-26 initial recovery dose, then a 10-3-13 booster dose midweek has created the single most algae-free, fast growing, healthy tank I've maybe ever had. The pearling has reached "upside-down rain" levels daily. The BDBS remains clean and algae-free, too.

How I've been fertilizing:
View attachment 11140
I prepare 4-5 weeks worth of GH remineralizer, initial doses, and booster doses in little 2oz cups.

I have been doing it this way because It's nicer to sit and spend 30-40 minutes making 5 weeks of doses in a single go, than to get the items out every weekend and measure/dose manually. It was also nice to "hold off" on making these doses if I wanted to change or experiment, but I'm ready to just make a Macros solution at this ratio (30-9-39) to make dosing easier. Remember, part of what matters when determining your fertilizer concentration (like 30-9-39) is the water change %. If you only perform 30% WC each week, 30-9-39 will quickly reach toxic/unwanted levels in your aquarium. Conversely, if you do 70% WC each week, you get a lot more leeway to experiment, but will have to dose as much as I do, or similar, to prevent your nutrients from bottoming-out. If you want to understand this or explore more, check out my Nutrient Accumulation Calculator!

Making a Macros Solution from scratch:

The first limiting obstacle is K2SO4, because it is the least soluble out of all 3 macros. If I add too much, it will never fully dissolve. So, I'll figure this one out first and go from there.

When you add enough KNO3 per week to get 30ppm NO3, you also inherently add 18.9ppm K. That's because it is KNO3. It contains both macros.
When you add enough KH2PO4 per week to get 9ppm PO4, you also inherently add 3.7ppm K (total 22.6ppm K from these two macros already).
I found these numbers through Rotala Butterfly.

That means I need to add enough K2SO4 to raise the final amount of K by 16.4ppm, to reach a total of 39ppm from all 3 macros per dose/week.

So, I need a solution with "reasonable dose sizes" that has K2SO4, that raises my tank's K by 16.4ppm. Since a mason jar will easily hold 600mL, let's use 600mL as the base for this solution (I love mason jars!):

For K2SO4:
View attachment 11141
Ok, so using the calculator, I've determined that I'll need 47g K2SO4 in 600mL to have a solution that, when 60mL are added to my 34 gal aquarium, I raise K by 16.4ppm. Great!
Side note, what happens if you make a solution too concentrated with K2SO4? You'll get a warning:

View attachment 11142
RotalaButterfly claims that the solubility of K at room temp is 120g/L (0.12g/mL), but that's the solubility at 77F... I don't know anyone who considers 77F room temp?! My room temp is much cooler, especially during the winter, and I find that K2SO$ will precipitate out (not fully dissolve) if I push it too close to this solubility limit in these cooler temps. Also, when making a macro solution with KNO3 and KH2PO4, which both add K, perhaps that affects solubility as well. Either way, I prefer to play it a bit safe near 80% solubility limit, instead of at 100%, so I can be sure all the K2SO4 will dissolve. And I tested it; K2SO4 does fully dissolve, even with the other macros present, at this concentration (0.08g/mL) at room temp or even cooler (67F).

Anyway, again, I now know I need to add 47g K2SO4 to my 600mL of water.

Now that I have K2SO4 out of the way, I don't have to worry much about the other two macros.
Both KNO3 and KH2PO4, at the levels we use them, are WAY more soluble than K2SO4 and they won't be a problem:

For KNO3:
View attachment 11145

For KH2PO4:
View attachment 11144

So, to make a macros solution where dosing 60mL into my 34 gallon aquarium raises the NPK by 30-9-39, Here's the "recipe":

In 600mL pure RO water, add:

• 63g KNO3
• 16.6g KH2PO4
• 47g K2SO4
• 0.25g Potassium Sorbate (anti-mold preservative)
• 0.25g Ascorbic Acid (lowers pH, helps anti-mold preservative work)

Once fully dissolved, I can add 60mL of this solution to increase my 34 gallon water column ppm to 30-9-39.

HOWEVER, since I have been LOVING the "mathematical consistency" of large water changes with large recovery doses, and a midweek booster dose, I will do two doses instead of one:

• After the weekly 75% water change on Sunday, I'll dose 40mL which adds 20-6-26 ppm NPK.
• On Thursday morning, I'll dose 20mL of the solution, which adds 10-3-13 ppm NPK.

And that's it!

Rather than measuring 2-3 different dry powders, betwteen fifteen cups (35+ measurements! on the scale!) every 4-5 weeks, this solution requires only measuring 6 ingredients on my scales (water, KSorbate, AAcid, KNO3, KH2PO4, and K2SO4) once and lasts for over 10 weeks. It's also already dissolved and easily dosed with a 20mL syringe and stainless steel needle.

Summary:

• KNO3 and KH2PO4 already add K on their own; discover this ppm already added, and subtract that from your desired K amount. That tells you how much K2SO4 you need to add to reach your total ppm K concentration in your solution.
• When making a Macro solution with KNO3, KH2PO4, and K2SO4, make sure you can fully dissolve all the K2SO4 you plan on using in your solution.
• Add them all together with a bit of Potassium Sorbate and Ascorbic Acid (or vinegar!) in pure RO water, and dose according to your solution's concentration relative to your tank's volume.

I know none of this is revolutionary, I'm just typing it out in case it helps someone understand how to do this themselves since I was taking the time to make a solution anyway.

This is great. I'm going to give your macros solution and dosing method a try. Thanks for taking the time to help people understand your methods.

 

[Naturescapes_Rocco]

Let me know if you want any help or to discuss specific numbers!

 

[TRyan]

Let me know if you want any help or to discuss specific numbers!

Thank you, I will likely have some questions, lol.

I have one already! Where do you source potassium sorbate
and ascorbic acid? Amazon? Any particular brand or tips about these 2 products?

 

[Naturescapes_Rocco]

Amazon! Get the smallest ones you can find, you will never use them all up. 1lb of either KSorbate or A.Acid is way too much, truly find the smallest amounts you can buy and get those.
For macros, 0.2g KSorbate / 500mL solution and 0.4g A.Acid /500mL too.

I add them last, because if you have only them in the bottom of the solution when you add water, they can sometimes seem to react with each other. Probably goes away with enough solution and other ions, but that's how I've been doing it.

 

[Koan]

For macros.. 0.4g A.Acid /500mL

Post in thread 'Shelf Life of Macros & Micros Stock Solutions?'

Jul 25, 2025

can just grind up some vitamin C

Pre ground 1g per capsule

• Koan

• 

Half a capsule = 0.5 G ascorbic acid, close enough for government work as we used to say in the Department of Agriculture

 

[TRyan]

I'm learning all kinds of tips today! This is so helpful.

 

[techman81]

This acrylic comes frosted from HD already! Just needed to design and 3D print some super fast brackets to hold it to the back of the tank in transparent PETG filament.

Is at least one side of this sheet smooth, so suction cups can adhere to it?

 

[Naturescapes_Rocco]

Is at least one side of this sheet smooth, so suction cups can adhere to it?

Yes it is!

 

[JacksonL]

10 day update:​

What happens when you set up a new tank? You have to go out of town, of course! Every damn time.

Diatom explosion occurred:
View attachment 9001
View attachment 9002
I'm not worried because it's just diatoms (they completely disintegrate when squished between fingers). They happen in every one of my tanks at the beginning, but this is a particularly bad case. Maybe because I didn't keep up with a few initial water changes (due to travel) or because there are lots of silicates in BDBS? Maybe @Burr740 could chime in with his experience with diatoms and BDBS.

I don't have a cleanup crew in there. Usually a few amano shrimp, cherry shrimp, otocinclus, and a few snails will decimate any diatom algae within a few days, but this one likes to keep coming back even after manual removal.

Same tank, just an hour later:

View attachment 9003

View attachment 9004
Mounted the auto doser to the top of the left door for easy access and viewing. Taking even small annoyances out of the way makes this hobby so so much more enjoyable for me.


View attachment 9005
I designed and 3D printed holders and brackets for all my testing equipment! Salifert Freshwater NO3, PO4, and K test kits, as well as my trusty Hanna CO2 test kit and a holder for my 10mL, 5mL, and 2mL syringes with stainless steel luer lock needles.

View attachment 9006
Designed and printed a bracket for the Brooks Flowmeter. This thing is SOLID, thanks to @Bettatail for the recommendation. Each line is ~5 sccm. The valve on this is good, but the needle valve on the regulator is better so I just use that to adjust my CO2. This flowmeter is much nicer and less "bouncy" than my Dwyer 151-RMA flowmeter I use on my large 150p tank.

More updates to come later!

Still reading my way through this awesome journal… but had to make a note of those beautiful test kit holders
The are so good!

Also, do you remember which model your flow meter is?

 

[Naturescapes_Rocco]

It's a Brooks Instrument Sho-Rate Flow Meter 1350EJ2CCFP1A 8.94-89.4.

Those numbers, 8.94-89.4, are the range of the flow meter in SCCM (the volume of gas per min).

If you are looking for flow meters, make sure they're super low in terms of SCCM. 90% of what is online have ranged WAY too large for our aquariums.

For reference, on my 140Gal, 150x60cm tank, I run ~42SCCM.

On this smaller 39Gal 90x50cm tank, I run ~13SCCM.

Also also, the Dwyer RMA-151 is a cheaper range flow meter that I find works just as well. It has a range of 0-50SCCM, which is better for smaller tanks.

On tanks as small as 25Gal or less, you probably can't use a flow meter because the only flow meters that can measure and adjust small enough changes in CO2 injection cost $500.

 

[GreggZ]

Also also, the Dwyer RMA-151 is a cheaper range flow meter that I find works just as well. It has a range of 0-50SCCM, which is better for smaller tanks.

FYI the Dwyer RMA-150-SSV has 10-100 CC/Min scale. Good for larger tanks. On my 120 G I run right about 50 cc/min so right on the high end of the RMA-151 range (0-50 CC/Min).

 

[Naturescapes_Rocco]

I should have included that! I actually use the 150 (10-100 scale) on my big 150p tank, thanks to your posts about it lol. Does yours still work great a few years later?

 

[JacksonL]

It's a Brooks Instrument Sho-Rate Flow Meter 1350EJ2CCFP1A 8.94-89.4. View attachment 13308

Those numbers, 8.94-89.4, are the range of the flow meter in SCCM (the volume of gas per min).

If you are looking for flow meters, make sure they're super low in terms of SCCM. 90% of what is online have ranged WAY too large for our aquariums.

For reference, on my 140Gal, 150x60cm tank, I run ~42SCCM.

On this smaller 39Gal 90x50cm tank, I run ~13SCCM.

Also also, the Dwyer RMA-151 is a cheaper range flow meter that I find works just as well. It has a range of 0-50SCCM, which is better for smaller tanks.

On tanks as small as 25Gal or less, you probably can't use a flow meter because the only flow meters that can measure and adjust small enough changes in CO2 injection cost $500.

Thank you, I am struggling to find one small enough for my tank. I have found one on Alliexpress of all places. Not sure how I feel about about it, but I had ordered one to try. $40 (Australian dollars) investment to have a try, if it goes in the bin it certainly won’t be my most expensive failure!

 

[TRyan]

These are the dosing tube holders. I had said 12 mm glass, and it’s really 10 mm, and I put a 2nd one on the neighboring tank (going from the same Chihiros doser) with even thinner glass. I had some black stick-on weatherstripping, so I just cut off a couple of slivers of that to make them snug. The tubing is very snug. I like these a lot better than the holders that came with the dosing system.

View attachment 9045

Wow, I like these! Where can I place an order? Haha, seriously though! I'd pay you for your time and shipping?

 

[Naturescapes_Rocco]

Wow, I like these! Where can I place an order? Haha, seriously though! I'd pay you for your time and shipping?

Sure, just send me a DM!

 

[GreggZ]

I should have included that! I actually use the 150 (10-100 scale) on my big 150p tank, thanks to your posts about it lol. Does yours still work great a few years later?

I would say mine is about a decade old. Still working great.

Like you said above, when looking at flow meters keep in mind this a VERY small amount we are measuring. So the scale makes all the difference.