Questions regarding softwater tanks

[Phil_1983]

Hello Apistogramma Forum,

I’m new to the community here, although I was a silent reader a few years ago.

Due to various life circumstances, I had to put my aquarium hobby on hold for several years. Now I’m finally returning and have set up a 180-liter aquarium (100 × 40 × 50 cm), in which I plan to keep some tetras and a male Apistogramma. I haven’t decided on the species yet.

My main goal, however, is to finally realize a true soft-water aquarium. I have an RO unit available and some limited experience. In the past, I always slightly remineralized the water (to around 100 µS/cm) for the sake of the plants. Back then, these were not true biotope aquariums, although there was a certain “blackwater look.” I’m happy to attach a photo or two of what I used to do in the past.

At this stage, I’m mainly interested in how I should approach this project. I’ve already read that using a large amount of, for example, wood, botanicals, and leaf litter is an important first step toward aquarium stability. But what else needs to be considered? How many plants should be added? Floating plants—yes or better not? Should I use pure RO water (around 8 µS/cm), or should I remineralize it slightly again?

How do I achieve a deep brown water color? In the past, I used a product from the German company DRAK. Do I need any additional products to ensure the well-being of the fish?

So many questions. Please excuse such an introduction. I would still be very grateful for any help

Best regards,
Phil

 

[MacZ]

Concerning plant choices: I've always worked with plants that cheat the low amounts of dissolved CO2 and the problem with lack of light. So basically I stick to floaters, floating leaves (Nymphaea sp., Nymphoides sp., Aponogeton sp.) and emersed plants like pothos or Monstera.

Water: I used pure RO, no remineralization, at best minimal fertilizer use (like 10-20ml liquid fertilizer per month) using the duckweed index.

About the colour: The lower the pH the lighter the water (just like with black tea and lemon juice). My tipp: Use a combo of rooibos tea and alder cones, make a tea-extract from that, let it cool, chugg it in.

Hope that helps.

 

[Phil_1983]

Thanks, that's helping a lot for now.

Just two more quick questions:
When you say tea-extract... What do you think how long I got to cook it? Really long to concentrate it or just a few minutes to sterilize?

And what kind of substrate would you recommend? I was going for fine silicate sand. Do you think this is appropiate?

 

[MacZ]

When you say tea-extract... What do you think how long I got to cook it? Really long to concentrate it or just a few minutes to sterilize?

You don't cook it. You put the stuff in a bowl or an other container and pour boiling water over, then let it steep. I usually used 2 liters of pure RO, 2-3 bags of rooibos and 10-20 small alder cones. Sometimes I added some pieces of catappa bark or leaves.

Sterilizing is not necessary. I mean, Rooibos is for human consumption (costs less than 0.25 € per teabag and alder cones ... why should terrestrial pathogens work underwater? They don't.

You can let the stuff steep either until its room temperature or until the next day. If you want to let it in for longer throw in an airstone, otherwise the microorganisms that settle on the botanicals use up the oxygen and different problems may arise from that.

And what kind of substrate would you recommend? I was going for fine silicate sand. Do you think this is appropiate?

Fine sand. Always. I used to do biotope tanks, so I tried to emulate the natural habitats.

 

[Mike Wise]

True blackwater streams in Nature have very few submerged plants. Most are emergent or floating plants. This is an example of a typical (flowing) blackwater stream. (Who is that guy anyway?)

 

[MacZ]

As visible in the picture there are aquatic plants nonetheless. In this case some kind of Nymphaea. The diversity of plants is also low. A few genera only.

True blackwater streams in Nature have very few submerged plants. Most are emergent or floating plants. This is an example of a typical (flowing) blackwater stream. (Who is that guy anyway?)
View attachment 17437

 

[Phil_1983]

Thank you both for the information.

And a special thanks as well for the clarification regarding the preparation of the tea,

 

[MacZ]

Little addition: you can reuse the alder cones. Dry them after the first brew, depending on quality 1-2 more brews are possible.

 

[Phil_1983]

Thanks again.

One more question about the substrate.

If I use fine quartz sand (0.1–0.3 mm), how thick can the layer be? Do the leaves and botanicals need to be added in sufficient quantities to cover the entire substrate? How thick can or must this layer ultimately be?

I understand that the mulm that forms over time remains in the tank. Are there any exceptions to this rule?

Please excuse all these beginner questions.

Translated with DeepL.com (free version)

 

[MacZ]

If I use fine quartz sand (0.1–0.3 mm), how thick can the layer be?

3-4cm

Do the leaves and botanicals need to be added in sufficient quantities to cover the entire substrate?

Just add over time and keep the mulm layer growing. I put in about 5 leaves a week, every week. The only exception to this botanical mulm would be mulm from leftover food and feces. That would be detrimental. But if you keep the botanical mulm this is countered. Keep the stocking densitiy low and only feed as much as needed.

Just take footage of my last tank as a reference:

What to do now?

Thanks for the condolences! I cam home with what is hopefully a pair an hour ago. One hour of drip to go. What is this plant on the left? Some species of Nymphaea? Classic Nymphea lotus, the Tiger Lotus.

apistogramma.com

You don't remove anything, btw. Just let the stuff rot down to mulm.

 

[Phil_1983]

I can only thank you again! I will have a look at your Thread.

 

[Mike Wise]

As visible in the picture there are aquatic plants nonetheless. In this case some kind of Nymphaea. The diversity of plants is also low. A few genera only.

True, but as I wrote "(m)ost are emergent or floating plants. Nymphaea are emergent plants.

 

[MacZ]

Missed that, my bad! Thanks for pointing it out!

 

[Dwarf_Enthusiast]

Little addition: you can reuse the alder cones. Dry them after the first brew, depending on quality 1-2 more brews are possible.

I collect local Alder cones, sterilize with an oven or food dehydrator, and toss them into all my soft water tanks. They are my favorite botanical because, in my experience, they last a very long time compared to leaves and they have always seemed to be a good home for the microfauna in my tanks. The advantage of using them as whole botanical instead of a "tea" is that they add a very naturalistic look, they are a great home for microfauna, they provide a lot of surface area for nitrifying bacteria to colonize, and you're likely to get a more "extended release" effect out of them.

 

[MacZ]

I've found them too much for my setup. If used in a tank the seeds should be shaken out of the cones, because those really tend to foul.

But as always with natural products: Mileage may vary.

 

[Phil_1983]

Since I am not a friend of wild caught fish in tanks, I ran into another question.
Do captive-bred fish have problems with soft water? And how would you go about introducing them? Drip method?

Not that it's relevant right now, but I'd rather find out in advance.

 

[MacZ]

Do captive-bred fish have problems with soft water?

Depends. While F-Generation fish (usually applied to up to 5 Generations removed from wild caught specimens) are often bred in softwater, they are in my experience hardier than domestic breeds dozens of generations (including line- and inbreeding) removed from their wild ancestors.

Interestingly the domestic breeds are often so inbred their general health and life expectancy are bad. ANd while they have often been bred for generations in tapwater, they do tend to do better in softwater. This is especially evident in colour breeds of M. ramirezi.

And how would you go about introducing them? Drip method?

I prefer drip method, but it definitely depends on the EC of the store/transport water and your tankwater. The higher the difference the more I advise to use drip acclimation.

 

[Phil_1983]

Okay, I understand. I will keep that in mind.
Thank you.

 

[Phil_1983]

Hey Guys,
it's me again. Since I am going to setup the tank this weekend, I have one question about the "cycling"-phase.

How many and how much water changes would you do?
After "cycling" (let's say 4 weeks), what would be your recommondation for water changes? I am planning 50% per week. Do you think this is feasible or too much/less?

 

[MacZ]

50% per week are a good start. If you work with emersed plants (Epipremnum, Philodendron, Monstera) and floaters to remove thing like nitrates and keep the stocking density low it might take a year until you can phase out waterchanges to once every few months and instead just have to top off with RO water.