'Low tech 5 gallon (previously 'Blackwater planted tank...thoughts?')

Joshaeus

Well Known
Hi everyone! I am currently trying to figure out what to do with my empty 5 gallon, and a blackwater planted tank is one of the options I am most strongly considering. How does this sound?
Tank; A 5 gallon that had been 'Prisca's pad'
Substrate; An inch of Canadian sphagnum peat moss (the Canadian part is important, as the amount Canada harvests is a 60th the amount of new peat moss produced in its territory every year and is thus sustainable) or perhaps a 50-50 mix of peat moss and sand, covered by an inch of turface.
CO2; A yeast reactor. The reactor will be weaker than that of my other 5 gallons and will be intended to add about 10 ppm CO2 to the tank.
Filter; A homemade bottle filter. Water will be pulled through two empty prescription bottles (with denitrate on the bottom and pillow stuffing and alder cones on the top) into a bottle filled with denitrate and a 60 GPH mechanical pump (to dissolve CO2...were it not for that need I would use an air lift pump). The design is intended to keep any fry born in the setup out of the pump.
Light; Possibly a 2700k, 50 watt equivalent BR20 LED bulb. This is subject to change.
Ferts; Custom. This is a blackwater tank, so they will be kept decidedly lean to keep TDS to a minimum; I may not dose calcium at all based on what fish eventually gets put in here.
Plants; Species that have done well for me in blackwater tanks in the past (most of which, unlike this one, had no fertilizing whatsoever). Such plants could include Mayaca fluvitalis, Rotala rotundifolia, and java moss, among others.
Fish; TBD. Some options include licorice gouramies (which would need a tank completely devoid of calcium if I intend to spawn them), a variety of wild bettas, Boraras or Sundadanio cyprinids, some killifishes...probably others I am not thinking of...

Thanks for your thoughts
 

FinalFins

Fishlore VIP
I think blackwater planted can work- ive seen it done for licorice gourami.
 

Joshaeus

Well Known
Hi again! I have started moving towards setting this tank up...I purchased 10 quarts of peat moss on amazon, 10 pounds of a very fine (and inert!) sand from the local petco, and already have heaps of turface lying around; the substrate will consist of 1/2 inch peat moss, under 1/2 inch sand, and covered by 1/2-1 inch turface. Turface absorbs prodigious amounts of ammonium with its CEC (as my other newish 5 gallon is teaching me in the form of ridiculous nitrate levels) and peat moss probably does the same, so I will likely dose ammonium in small amounts twice a day instead of one big dose at night during the cycle to prevent the substrate from absorbing quite as much, and take several weeks after the cycle is finished to remove the excess nitrates thus produced. The ammonia oxidizing archaea that are likely to dominate the filter fauna can fix CO2 as a carbon source, so dosing small amounts of CO2 will likely make their life easier.

As for plants, I am thinking of using the following;
- Mayaca fluvitalis OR Hygrophila difformis (background)
- Dwarf water lily OR small sword plants (midground)
- Java moss tied to glass pebbles (foreground side...the middle of the foreground will have a leaf pile instead)
 

Joshaeus

Well Known
Hi again everyone! I decided to make this setup more adaptable in the event we move at some point to somewhere with harder water. Here are some changes I am likely going to make;
Water; 1/2 softened water, 1/2 my tap water. Going to shoot for TDS between 60 and 100 ppm, which should be acceptable to all but the most delicate fishes. Ferts will still be limited to manage TDS.
Filter; an air lift driven filter; going to shoot for about 30 GPH (likely via a 1/2 inch ID air lift). This also means I will not be using CO2, which will make the setup more simple.
Fish; Probably not licorice gouramies (except perhaps the hardiest species like Parosphromenus linkei) but wild bettas and many killifishes are still options. Pygmy sunfishes may also do well in this setup, as may Neocaridina shrimp if the GH is kept high enough.
Plants; Probably the same options as mentioned before (perhaps with others due to the less hostile conditions)

Thanks for looking thus far I am running into issues making a working water softening filter, which also prompted this shift.
 

Joshaeus

Well Known
Hi again everyone! I found a really cool article on Utricularia graminifolia; Utricularia Graminifolia - Aquazone

Apparently this plant grows best with very lean (or non existent) fertilizer, a soft and acidic substrate with no ferts (peat moss and gravel worked best in the above article), and with live food readily available to the bladders at its roots (like most carnivorous plants, U. graminifolia gets most of its nitrogen and phosphorous from its prey). This sounds like a VERY good candidate for this blackwater setup...I may give it a try as a carpet.
 

Joshaeus

Well Known
Hi everyone! Tank setup has begun I got the peat moss in the mail today, so I placed 6 cups of peat moss at the bottom, 5 cups of sand above that, and 6 cups of turface on top, roughly smoothing out each layer before placing the next. I am going to add a little bit of water later today to help get the peat moss soaked.

As for what direction this tank is going...I've had a rough couple of days and I am really not 100% sure where this tank is going. I am divided between either making it only slightly acidic or going all out PH 4 blackwater, and regarding whether to use CO2 or not (and thus whether to use a mechanical or air lift pump). Forgive me for all of this confusion...I will decide in a couple days. Thanks for your patience
 

Joshaeus

Well Known
Any pictures?
Yes, actually! In fact, I went ahead and set this tank up...here you go;

Blackwater planted tank 10 19 2020.jpeg
The filter is several prescription bottles attached to each other with tubing, filled with seachem denitrate and pillow stuffing and powered by an air lift pump...it actually has surprisingly strong flow. Water parameters when I took this picture were 10 ppm TDS and a PH of about 6.5, and I added seachem stability and 1 ppm ammonia to get a cycle going. I will most likely not use CO2 with this setup, but I am still planning on lightly fertilizing to make the life of the plants slightly easier.

I also came up with a possible dosing regime...it's quite lean, but otherwise fairly complete. How does this sound? (I did not include calcium because licorice gouramies, the species I am most strongly considering for this tank, will not breed successfully if any substantial amount of calcium is present...if I opt to keep something else I may add a small amount of calcium);

OVER COURSE OF WEEK (per 18 liters);
*Through days 1, 3, and 5;
- .0875 (1/2 of .175) ml KNO3 (4.06 ppm NO3, 2.56 ppm K, 6.62 ppm TDS)
- .04375 ml (1/4 of .175) KH2PO4 (1.9 ppm PO4, .62 ppm K, 2.52 TDS)
- .0875 KCL (4.39 TDS, 2.29 K)

*Through days 2, 4, and 6;
- .0875 ml Plantex CSM+B (.27 ppm iron, less than 1 TDS?)
- .175 ml epsom salt (2.28 TDS, .97 Mg)
 

Joshaeus

Well Known
Hi everyone! I discovered this morning that dosing ammonia to such a soft tank is not a good idea...when I tested water parameters this morning, not only had the TDS increased to 21 ppm (likely due to contaminants in the ammonia I had been using) but the PH had shot up to 8.5 - obviously not acceptable in a blackwater tank. Going to be doing a 40% water change in a few minutes to help amend this and perhaps dose some citric acid with it to help neutralize the excess ammonia.
 

JustAFishServant

Well Known
That sounds great! But if you do decide to go with this setup, *please send pics*, for I am obsessed with blackwater!
 

Pfrozen

Well Known
To be honest, your style is too advanced for me, so I can't comment much lol. At the rate I'm going though I'm sure I'll be right there with you soon :/ I'm already putting like 6 things in my tank every morning now

The only thing I will say is that my experience with Canadian Peat Moss is that after a few water changes it stopped buffering my pH entirely. My tank sits at the same pH as my tap water now. Which is fine by me, I just can't spawn my rasboras. At least I get to keep shrimp and snails now. For reference, my substrate is 30% peat and it's 6 inches thick in some spots so I have quite a bit in a 20 high
 

Joshaeus

Well Known
To be honest, your style is too advanced for me, so I can't comment much lol. At the rate I'm going though I'm sure I'll be right there with you soon :/ I'm already putting like 6 things in my tank every morning now

The only thing I will say is that my experience with Canadian Peat Moss is that after a few water changes it stopped buffering my pH entirely. My tank sits at the same pH as my tap water now. Which is fine by me, I just can't spawn my rasboras. At least I get to keep shrimp and snails now. For reference, my substrate is 30% peat and it's 6 inches thick in some spots so I have quite a bit in a 20 high
That's a lot of peat! Yeah, I just wanted a substrate with lots of CEC that would not increase the TDS much...peat moss fits the bill. I am looking for other ways to push the PH down...

That sounds great! But if you do decide to go with this setup, *please send pics*, for I am obsessed with blackwater!
Thanks! I will be making this either a genuine blackwater tank (with lots of leaves and other botanicals as the primary decor) or a hybrid blackwater/planted tank, but there WILL be pictures as the tank progresses.

Speaking of the tank...just did the aforementioned 40% water change. To the 8 liters of new water I added .525 ml citric acid, partially to neutralize the ammonia and partially to reduce the PH...on the latter front I may have succeeded, as the PH is in the mid 4's now - a very good value for licorice gouramies. Will that value stick? Time will tell...(The TDS post water change is 25 ppm, coincidentally)

EDIT: A few minutes ago I tested the tank again (not for any particular reason...I just tend to get obsessed with that kind of stuff) and discovered the PH had dropped to 4 (the lowest the test kit measures) and the TDS had dropped to 23 ppm, perhaps because the highly acidic conditions ionized the ammonia to ammonium (which, as a cation, is vulnerable to the cation exchange capacity of the turface and the peat moss). Will probably use less citric acid next time (perhaps closer to .175 ml per 8 liters) unless the PH unexpectedly climbs by the next water change. Stuff like this is why you cycle and mature tanks sans livestock.
 

Joshaeus

Well Known
Hi everyone! The citric acid not only did not hold the PH down (the PH is now at 6.5 again) but now the tank has a bacterial bloom. Not really surprised in retrospect...citric acid is one of the primary energy sources for all aerobic (oxygen using) life, and many bacteria can directly eat it. For Friday's water change, I am going to try to use some API PH down I have lying around and see if it does the job...even for a tank this soft, my calculations suggested I may need to use considerably more than the recommended dose just to overcome the bicarbonates formed when CO2 dissolves in water at a PH of 6.5, and I will likely be using somewhere between 6-12 drops per 8 liters of new water change water (plus an equivalent amount for the water already in the tank...the tank is nowhere near cycled yet and has neither fish nor plants, so why not?). Even at a PH in the 4's, small amounts of bicarbonate do form when CO2 dissolves in water and will slowly react with the sulfuric acid in the PH down, so the tank's PH will likely climb slowly over the week (unless the acid is completely neutralized, in which case the PH may jump...hence the desire for well over the minimum amount of acid required). This seems to explain why my prior blackwater tanks tended to have issues with the PH going up without my consent, not down...

EDIT: I made 8 liters of softened water and added 12 drops of API PH down to it. To my surprise, this sent the TDS shooting from 2 ppm to 30 ppm, and the PH was lower than the test kit could measure...I think I got my math wrong somewhere along the way. I replaced 2 liters of the highly acidified water with new softened water to get the TDS to 22 ppm (still higher than I'd like), but the PH was still VERY low (using a PH calculator suggests that the PH could be as low as 3.65! A lot of blackwater fish would be ok with that, but it's still overkill)...I think I will shoot for 4 drops of the PH down next time with the 8 liter water change, and won't add any additional PH down to the tank itself when I do a water change Friday.

In other news, I am currently soaking 5 birch cones that I purchased a while ago from tannin aquatics in tap water to loosen the dirt off, and will then be placing them in the blackwater I made after giving them a good rinse.
 

Joshaeus

Well Known
Hi everyone! This is not directly about the tank itself (which hasn't changed much), but rather about how I am creating water for it. As of today I have two ways of creating the uber soft water required for this tank; both allow me to recycle old tank water and save money on the mixed bed resin used to do the softening.

The first is to pour water into gallon jugs with mixed bed resin, cap and shake the jugs for 20-25 seconds, allow the resin to settle, then use a gravel vacuum to remove most of the water and pass it through a 25 micron sieve (to catch the resin), stopping the siphon when the water is about half an inch above the resin. I've used variants of this method for a while, and while this is a very fast method it is undeniably tiring to shake a gallon bottle repeatedly.

I just developed a second method today involving small water pumps (which accept 5/16 ID tubing), a barbed reducer (5/16" ID to 1/4" ID), a five gallon bucket, and inline mixed bed cartridges that accept 3/8" inch tubing (which is 1/4" ID). I use the barbed reducer to attach the tubing from the water pump to the inline mixed bed cartridge and turn the pump on at its lowest setting (the inline cartridges I use only support a flow rate of up to 30 GPH) while all parts are in the bucket. This is much slower than the above method but also much less tiring and can be left alone for extended periods; I do not know exactly how slow it is because I have not made extensive tests of this (I just figured this out today). You can set multiple pumps going in the same bucket (each with one mixed bed cartridge at the end...they don't work well with multiple cartridges per pump) to hasten the process.

EDIT - It took about 80 minutes for these two pumps to push the TDS of 16 liters of water from 48 ppm to 4 ppm, so this second method is definitely quite slow...I might look into an RODI unit. Alternately, I could simply leave these pumps to their own devices all day (something I could not easily do with an RO unit, as I have nowhere to permanently attach one).
 

Joshaeus

Well Known
Hi everyone! Ran into a snag with this tank...I did a 12 liter water change (almost the entire tank volume above the substrate) yesterday, and the new water had 7 drops API PH down per 4 liters. In spite of that, the PH has increased back to 6.5 by this morning...me thinks I am not going to be able to keep the PH down below the 6's long term. I have thus made an executive decision to turn this into a low tech, likely walstad or walstad like, planted tank...going to rename this thread as soon as possible to reflect that. For now, I have placed a new geyser air lift pump (it's technically a filter, but I did not put filter media in it because it is going to be a walstad tank) in the tank and reduced the water level somewhat to improve the surface area (and thus gas exchange).

EDIT; Does this sound like a good 'dosing' regime for when I do water changes? (Likely every 4 weeks once the tank is established, more frequently for the first two months);

Dosing per 8 liter water change;
-3/8 tsp CaCL2 2H2O (46 ppm calcium, 6.53 degrees GH)
-1/8 tsp epsom salt (7.89 ppm magnesium, 1.81 degrees GH)
-1/8 tsp KHCO3 (33.56 ppm K, 2.41 degrees KH)
-1/4 tsp baking soda (38.74 ppm Na, 4.72 degrees KH)
 

Joshaeus

Well Known
Hi everyone! I did an 8 liter water change this morning with much harder water to start adjusting the tank towards being a low tech planted tank...the new water had a GH and KH of 12 and 9 respectively, which was higher than intended (will likely go a little easier on my homemade salt mix next time...1/2 tsp per 8 liters instead of 3/4th tsp). I am also planning a list of plants for this tank...how does this list sound?
-Italian vals
-Ludwigia 'super red mini'
-Red flame swordplants
-Dwarf sagittaria
-Frogbit (I created a calmer area with airline tubing for the frogbit)
 

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