plant newbie

[chloroplast]

Hello,

I am trying to grow an aquatic carnivorous plant (Aldrovanda) and I have a few questions regarding general plant care. (I know the specific requirements of Aldrovanda.) Any help would be greatly appreciated.

Background:
10gal covered tank, 65W florescent light ~4" above the water, water temperature=75F, aerator for oxygen. Substrate consists of 2"peat-->1/2" silica sand-->3" decaying sedge and cattail leaves-->5" distilled water made acidic (pH=5.5-6) with peat tea solution. The decaying peat and plant matter provide CO2. Living noncarnivorous plants include water hyacinth and duckweed, and there are 2 water snails to help control algae. Recommended dose of "Plant Gro" added (0.15 - 0 - 0) to enrich water.

Questions:
1. Are there any test-kits availabe for testing [CO2]?
2. This tank is not filtered because Aldrovanda likes calm water. Generally, are there any problems with mold/fungus in unfiltered water?
3. How significantly does the aerator decrease [CO2]?
4. Any advice on CO2, controlling algae and other factors that I may have overlooked would be appreciated.

I thank the all-knowing gurus for their time! :bowing:

 

[ChicoRaton]

1. Are there any test-kits availabe for testing [CO2]?

It can be tested by measuring ph and kh. Do a google search for chuck's planted aquarium calculator.

3. How significantly does the aerator decrease [CO2]?

With no co2 injection, and aeration, your co2 will always be at equilibrium with the atmosphere. aeration makes all dissolved gases maintain equilibrium with the atmosphere.

4. Any advice on CO2, controlling algae and other factors that I may have overlooked would be appreciated.

You have a lot of light, so keep your nutrients well balanced. You will need to increase the hardness(kh) of your water if you want to inject co2. Adding co2 to distilled, already acidic water will make the ph plummet and may kill your plants.

hope that helps. your setup sounds cool!

 

[chloroplast]

thanks for the reply; your answers certainly helped......but they also raised a few more questions. So, if you don't mind:

1. Your comment on aerators equilibrating water gases worries me. Aldrovanda requires high CO2 in the tank, so I may have to remove the aerator. On the other hand, like most living things, this plant also requires O2. In general, can plants be grown in aquaria without aerators? i.e., what are some of the negative consequences of not using an aerator?

2. Can an aquarium be maintained without using a filter? This may sound like a stupid question, but what does a filter remove from the water (gases, nutrients, big particles, dissolved stuff)? THIS IS PROBABLY THE MOST IMPORTANT QUESTION.....if the filter removes nutrients or CO2, or if it adds anything or changes the pH in any way, I cannot use one.

3. Without the use of a filter or aerator, does mold/algal growth become a serious issue? Will the water stagnate too much?

4. Regarding your comment on maintaining balanced nutrients..... how can this be accomplished. What mix of nutrients is best for reducing algal growth....I imagine low N and P.

Oh, and thanks for saying my setup is cool.... I've put a lot of work into it and it think it's pretty nice. You'll have to excuse me if my questions seem ridiculously simple.....though I've had aquariums as a kid, I never gave much thought to the details, and this is the first time I've tried growing an aquatic plant (and this particular species is challenging to grow to boot)! Thanks again for your time.

 

[happychem]

Plants grow very well without an aerator. With enough CO2 and proper nutrient balance, plants will quickly saturate the water with O2, then supersaturate, then a little more to produce O2 bubbles, refered to as pearling.

In any case, yes, you can do just fine (probably better) without an aearator.

A filterless aquairum, well, yes and no. If your plants are really growing well, they'll consume most of the NH4 produced by fish. I didn't notice you mentioning fish, will there be any? If you aren't adding fish, you can probably get away without one, especially if you're up to speed on your water changes. A filter in a well growing planted tank helps to clear out decaying matter (old fish scales, dead leaves), which it looks like you're not interested in doing , water circulation, which can be provided by a powerhead, and biological filtration for any NH4 your plants don't consume. Again, if you aren't adding fish, then you can most likely get along without one.

A filter will not 'remove' CO2, but if your water level is too low and/or you don't cover the outflow with a sponge, then it can produce splashing at the surface which will help dissolved CO2 reach air equilibrium.

Fill your filter with foam/sponges/floss/wool only (skip the carbon and ammosorb-type inserts). This will not remove any nutrients from your tank.

Nutrients can be balanced by the addition of KNO3 for N, Fleet enema for P. By supplying N and P individually, you can adjust whichever needs boosting without directly affecting the other.

 

[chloroplast]

Hi Happychem,

Thanks for the reply. Perfect, looks like the aerator is getting chucked! Also sounds like I won't need a filter either since there won't be any fish, the water depth is only 5", and maintaining the decaying matter is essential. The only animal life I have in the tank are 2 water snails to remove algae.

BTW, if you have any non-chemical algae-controlling tips other than snails, having plants to outcompete the algae, keeping N low, and acidifying the water, please feel free to let me know. I can't use Cu or Al-based algicides because they kill the Aldro. Seems like the Aldro also hates the "safer" algicides that can normally be used in aquariums with plants.

The only thing left is to buy a tank divider. I just realized that the Aldro likes a lot of light. Though the duckweed and hyacinths may remove excess nitrates, they also block out most of the light.....so, I'll keep them on one side of the tank and let them do their thing, while keeping the Aldro on the other and letting it get its light!

Thanks again Happychem and ChicoRaton for your help.

 

[chloroplast]

Actually, a couple of xtra questions, if you don't mind:

1. Can I get a kH testing kit at Petco? The store is a while away and I would rather not drive if they probably don't have it. Also, does the package say "kH test kit" or something straightforward like that? This is the first time I've bought such a product, and the employees at my local Petco haven't been much help answering questions. I apologize in advance for the ridiculously simple questions.

 

[happychem]

Yeah, they should have KH test kits, probably coupled with GH, something like: "GH/KH" will be on the box.

You can build a corral of sorts using airline tubing, suction cups and aquarium safe silicone. Silicone the suction cups to the ends of the tubing, make sure you get a good airtight seal. The tubing should float. Use the suction cups to postion it in a loop around the water over your Aldro. The duckweed can grow up to the loop, but the floating tubing should keep the majority of the water over your plant clear.

As for algae, lots of water changes. With all that decaying material, you're bound to have mega nutrients. I'm really not familiar with what you're doing, but I gather you're going for lots of detritus. Figure out the NO3/PO4 level you're going want, assuming it's higher than the standard (10-15 NO3, 1-1.5 PO4) and use water changes to keep that level constant.

 

[TKOS]

Amano shrimp also might help if you can find them. They woudl probably do well in that setup.

 

[chloroplast]

Thanks guys....

I like the idea of the corral; this will allow the duckweed (which houses the daphnia that the Aldro eats) to remain near the carnivorous plant.

Regarding algae control, shrimp sound good, especially since they absolutely won't eat the Aldro (unlike the snails, which sometimes nibble). Unfortunately, I can't find the shrimp at my local petstores.

On an equally important note, I bought a water test kit and here are the results. I bought the kit to measure KH and pH so that I could calculate CO2. Unfortunately, the test didn't measure KH directly (at least I don't think it did). Here are the results:

total hardness: 50ppm
alkalinity (buffering capacity): 100ppm
pH: 6.8
nitrate: 10ppm
nitrite: ~0ppm

The conditions that Aldrovanda enjoys are:
pH: 5.6-6.8
CO2: 1-2mM
NO3: 0.3--0.6 mg/l
NH4: 1.0--1.5 mg/l
PO4: 0.06 mg/l
K: 2.4--4.0 mg/l K
Ca: <40 mg/l Ca,
Mg: 6.0--15.0 mg/l Mg,
Na: 8.0--13.0 mg/l Na,
Fe: 0.5--1.0 mg/l

My questions are (I think some of these questions are perfect for Happychem!):

1. Based on these results, can anyone tell me the level of CO2? I realize that there is a pH/KH/CO2 chart, but at this time, I don't think I can use it because I don't have KH.
2. My information source states that Aldrovanda likes CO2 at 2mM or higher. I believe they probably should have stated it in terms of molality or normality (instead of molarity), since we are dealing with [CO2] in aqueous solution. Semantics aside, I think that 2mM CO2 = 0.088g/L CO2 = 88mg/L = 88ppm. Is this correct?
3. This is a relatively high level so I would like to add CO2 to the tank using the yeast method. If I do this, I will probably have to increase my alkalinity (KH?, GH?, buffering capacity?) to keep the pH from radically changing. I imagine that adding baking soda would do this.
--How much baking soda should be added (there are ~3-4 gallons of water in the tank)? Should I even be messing around with alkalinity, etc. considering that I'm a novice when it comes to aquarium chemistry. .
--Would adding baking soda elevate the Na levels too much for Aldrovanda? (it likes Na=8-13mg/l). If so, are there any alternatives? I've heard about calcium carbonate (Aldro likes Ca <40mg/l), and if this turns out to be better, where can I get it (there's none at Petco)?

Once again, I apologize for the verbose post. Aldrovanda is perhaps one of the most challenging carnivorous plants to grow indoors. I've posted similar questions on several carnivorous plant forums that I am a member of, but most members have little experience with aquarium chemistry (most CPs are not pure aquatics). Thanks again.

 

[happychem]

I don't know what you mean by "didn't measure KH directly". The alkalinity test is a straightforward strong acid titration. There really isn't a way to measure KH directly, well, at least for hobbyists. You have to make the assumption that other contributors to alkalinity are small or negligible. In most cases the only one that may be an interferant is PO4.

So it looks like you've got about 27ppm CO2, but like I said, it depends on your interferences.

Yes. 2mmol/L * 44mg/mmol = 88mg/L ~ 88ppm

In a 10g with 4" of water, you can probably get there with yeast CO2.

As for baking soda, I don't think that you really need any. With an alkalinity of 100, you're pretty stable. Aim to bring pH down to about 6.4-6.3.

Given the narrow range of Na, I think you'll have a hard time getting into it anyway.