trying two tanks and two methods two different problems

The 46 gallon tank is too low on light. The depth of the tank makes it effectively even lower on light - the amount of light reaching the substrate is much too low. I suggest adding a second 55 watt light.

You can't judge your CO2 concentration by bubbles per second. That 2-3 bbs could end up giving you little more than atmospheric concentration of CO2 in the tank, depending on how you are introducing it into the tank. If you get a cheap little drop checker you can easily see if you are even close to having enough concentration.

You don't mention filtration, but the 46 gallon tank needs good water circulation to keep fertilized water available to all of the plants. That can be from a canister filter with carefully positioned outlet in the tank, a powerhead, or both.

I have had no success with a ten gallon tank either, so I will leave that one for others to comment on.

 

If you're doing co2, you really need drop checkers for both tanks, especially so with diy. There's no other way of accurately determining co2 concentration in the water, there are too many other variables (such as diffusion efficiency, circulation and offgassing, etc.). It's not really worth trying to fix anything else, until you get a handle on your co2.

 

I think the priorities should be:
1. Pick a tank that is good for plants.
2. Pick a substrate that is good for plants.
3. Pick an adequate light fixture for your plant growth goals.
4. Set up a CO2 system that provides the CO2 you need in a stable way.
5. Pick a fertilizing method that provides non-limiting amounts of NPK and traces.
6. Pick the plants that are appropriate for the light you have and grow at the rate you want.
7. Study the Barr Report again!

 

My 10 gallon non-co2 tank does quite well, especially for a non-co2 environment. It seemed to take a lot longer to become stable, though. I have two 11 watt cf's on it. I did have some issues with bba a little while ago, which I got rid of by fixing the problem (sunlight was hitting the tank) and pruning/bleach dipping badly affected plants, and upping water changes for a while. I only keep hardy plants in it though.

 

If those lights have good reflectors, I think you need at least 70 or 75 watts, unless you restrict yourself to anubias, java ferns, maybe some crypts. To grow most plants, again with good reflectors for those bulbs, my experience suggests that the minimum is at least 80 watts. Those numbers are for a tank with the usual 16" or do depth. Having a 22 inch deep tank makes it harder to get enough light at the substrate level without still more light. That's why I suggested you go with 110 watts. I use that amount on a 45 gallon tank, but only about 16" or less deep, and I can get good growth of almost all plants I have tried.

If you assume the intensity from those lights drops off proportional to the distance from the bulbs, a pretty good assumption, you would need 22/16 times as much light as I have, or 150 watts to have the same substrate level intensity that I have.

All of that is little more than a crude analysis, but I think it does suggest that you need more light.

 

hoppy, I can't see the rational of adding more light in the face of an algal bloom. It seems highly unlikely that the bloom was triggered by insufficient light and it seems even less likely that doubling the light now will help at this moment. certainly, once the algae problem is solved lighting increase would be called for.

It seems to me that it would help to determine specifically what kind of algae is present in order to give us a clue as to cause.

It's easy to claim to be dosing EI but how many times have we seen where the poster had massively under-dosed while all the time thinking that his/her dosing was adequate? So we'd have to immediately suspect dosing or poor CO2/flow before moving on to increasing the light.

filipem, perhaps you could explain exactly how many teaspoons or grams of KNO3/KH2PO4 you are dosing and with what frequency they are being dosed? If you had mixed the powders in water could you tell us how you prepared the mixtures?

Could you also confirm that your dropchecker is filled with 4 kH water and not tank water or tap water?

Could you also identify the type of algae you are getting? You could have a look here for identification if you are not sure of the names=> James' Planted Tank - Algae Guide

Also, what type of filtration is the 46G using? many times the tank is under-filtered causing poor ammonia removal and poor flow distribution which can result in nutrient deficiency even when dosing proper amounts.

Cheers,

 

I agree that the algae won't get better just by adding more light. My only point was that the plants won't grow well without more light, and healthy growing plants is the first defense against algae. I still believe that once we select a particular tank and substrate, the light is the next thing that needs to be selected, followed by a fertilizing, including CO2, regime. Only after those are well selected do you have a good shot at establishing an algae free tank.

My first thought on reading the original post was that a few of the basics needed to be corrected before going into the subject of algae. And, the light was the first thing I noticed. I didn't even mention the second thing - that seems to be a tank with too much fish in it too. I don't have experience with Discus, but as I understand it, those fish require lots of water changes to control the contamination they cause. And, four in a 46 gallon tank, unless they are very small and are going to be kept very small, is too many.

 

I would consider that tank very under-filtered. That filter isn't large enough for a 29 gallon tank, let alone an overstocked 46 gallon.

On the 10 gallon tank, I would reduce photoperiod to 6-7 hours, and see if your algae reduces. Give the plants some time to adapt to your tank, and once they take root, should grow better.

 

Hi filipem,
Thanks for additional data. It's pretty clear to me now as I can see a few things wrong with the technique and this explains a lot.

1. First and foremost is that you cannot reliably measure CO2 levels using tank water or any other water except for distilled water adjusted to some known kH value. The reason is that the reagent you add to the drop checker is merely a pH reagent. CO2 dissolves in the dropcheckers water sample and makes it acidic. The reagent measures this acidity and there is a relationship between the kH, pH and the amount of acid created by the CO2 (Carbonic acid). If you use tank water in the drop checker though you will corrupt the readings because there are all sorts of acids dissolved in your tank. Even the PO4 that you add as a nutrient will create Phosphoric acid. What happens then is that the dropchecker pH reagent will read a much higher acidic content due to these other acids but is unable to determine how much of the acidity is due to CO2 alone. So you will always read a higher acid content and therefore a lower pH as a result. The drop checker turns green sooner than it would and so you have a much lower CO2 content than you think. This is why the dropcheckers water needs to be "isolated" from the tank water. It needs to be distilled water free of any other acids so that you are measuring ONLY carbonic acid and no other acids. When this distilled water is adjusted to be 4 kH then it just so happens that the pH is approximately 6.6 when the CO2 content of the sample water is 30 ppm. The fact that you are using water of unknown acidic content in your dropchecker partially explains why you have BBA, which is a CO2 related algae.

Check out this dropchecker tutorial: Welcome To UKaps - CO2 Measurement Using A Drop Checker

2. The nutrients you are using are great but your application of them is less so. If you have a dosing scheme then there is no need to measure NO3 or PO4. Your test kits are getting you in trouble because they are inaccurate. Sometimes they lie to you and tell you that you have more NO3 or PO4 than you actually do so you respond by reducing the dosing and the plants starve, causing algae. This could easily be a primary cause of your BGA, which indicates low nitrates.

A 46 gallon tank should receive the following baseline dosing scheme:
1/2 teaspoon KNO3 3X per week
1/8 teaspoon KH2PO4 3X per week
1/4 teaspoon Chelated Trace element mix 2X per week

You do not need to add K2SO4 because you get enough K from the KNO3.

If you add these quantities you never need to test. This is the EI principle. Testing is clearly getting you into trouble because you are no doubt responding to false readings. If you add these quantities consistently then you are guaranteed to have sufficient nutrient levels regardless of what the test kit readings say. You need to put your test kits away and just dose the above consistently. Check this EI dosing primer: Welcome To The UK Aquatic Plant Society - The Estimative Index (EI)

In high tech tanks biological filtration is super important. The reason is that the ammonia production generated by the organic waste produced by plants and animals is not consumed quickly enough by the plants alone. Ammonia plus high light triggers algae as you have clearly seen in your own tank. In a high light regime the nitrifying bacteria do the work of converting ammonia into nitrate. Higher fish loading creates higher ammonia which requires higher bacteria populations to nitrify. So the larger the filter the more biomedia can be used and the higher bacteria populations can be generated. Additionally, higher flow rates generated by larger pumps create better flow. This flow reduces stagnant areas and delivers nutrient and CO2 laden water to each leaf. The higher flow also helps to carry away waste products from the plants and to keep detritus in suspension longer to be taken away by the filter inlet. The idea of low filtration requirement in a planted tank comes from long ago when the lighting technology was not as advanced as it is today. The more lighting you have the greater the need for high powered filtration. I typically suggest a filter throughput rating of 10X the tank volume per hour. For 46G that means 460 GPH filter rating. The rating is a little bogus because filter are rated at about twice what they actually deliver when installed and filled with biomedia.

I reckon that if you implement the suggestions above, with the water change schedule you have there should be little difficulty keeping the stocking levels you have, your algae issues will disappear and you will be able to use that second bulb as hoppy suggested.

Cheers,

 

Very nice post ceg4048. You did a great job putting everything together. I think if Filipe follows your advice then he has a good chance of whipping things back in shape.