Dying plants and algae bloom

[pondholler]

I've been reading up here on algae blooms and am not sure where to start to remedy our problem -- dying plants AND a green-water algae bloom.

We have a 300 gallon freshwater planted tank which is underpopulated mostly with various tetras, angelfish, algae eaters and catfish. We've been managing it with weekly water changes without any problems for about 8 months now. However, though the tank is well-lighted, our plants have never thrived. Even the hornwort has become so weak it breaks apart when handled. So we decided to fertilize with NilOCG Thrive Caps. Within about 10 days, our plants looked even worse and we had a green-water algae bloom. Did a huge water change and turned out the lights for three days. That seemed to help with the algae, though the plants looked no better even with lights back on. Within a few days the algae bloom returned and we did another huge water change and turned the lights off again. And that's where we're at.

A few more details. We've been using API StressZyme after weekly water changes. We have a canister filter and two pumps which, among other things, keep the water pretty warm (80-82F in the summer) without a heater. I just tested the water (post water change) and it read 0 ppm for Ammonia, Nitrite, and Nitrate. We've been feeding small amounts of flake food and sinking pellets twice a day. Because our plants seemed to be struggling, we changed our lighting about a month ago to a Hygger (HG-978) lighting system which emits "orange light at dawn, full spectrum light at day and blue light at night" (evening) -- this is from 6:00 am - 6:00 pm. It has 6500-10000 kelvin and 2365 lumens.

From what I'm reading, the StressZyme might be a bad idea. Will definitely cut back on food as well. I've ordered some Water Sprite plants to replace the Hornwort as floaters. I am rather confused about the lighting as we thought we were doing the right thing by the plants, but the good news is that the system is pretty flexible and I can cut back on whatever is too much (fewer hours, less full-spectrum light, etc) if I just know what direction to go in.

We'll read any and all suggestions with great interest. Thanks.

 

[Alice B]

I'd cut back on the sinking pellets and never feed more than once a day. Specific plants require different things, but when I tried an aquatic plant food with nitrogen what I was got was an algae bloom. @StevenF knows a lot about minerals and plants and helped me straighten my tank out.
Sinking pellets are something I would not feed more than once a week though, they are notorious producers of cyanobacteria and a couple of other algaes, including black and red brush algae

 

[pondholler]

I'd cut back on the sinking pellets and never feed more than once a day. Specific plants require different things, but when I tried an aquatic plant food with nitrogen what I was got was an algae bloom. @StevenF knows a lot about minerals and plants and helped me straighten my tank out.
Sinking pellets are something I would not feed more than once a week though, they are notorious producers of cyanobacteria and a couple of other algaes, including black and red brush algae

Thanks for the tip on sinking pellets AND the plant food. We suspected it might be part of the problem.

 

[Byron]

There are a few issues here, some of which you have already guessed at. To get one out of the way quickly, don't use StressZyme. While I and most consider API a leader in the hobby, they still have some products that frankly should never enter an aquarium, and this is one of them. The claims they make for this chemical concoction are beyond logic. Only two chemicals should ever go in a tank with live fish...conditioner and--if necessary--plant fertilizer. API's Tap Water Conditioner is superior because it only deals with what needs dealing with, and in detoxifying the heavy metals (some of which are essential plant nutrients) it does not use chemicals that prevent plants from taking these detoxified metals up. Liquid plant fertilizer that is comprehensive maybe, let's leave that for now because currently this will only feed the green water.

Staying with additives...NilOCG Thrive Caps don't look too bad, but they are certainly not good. Seachem's Flourish Tabs are far superior. For one thing, FT do not have nutrients that will get into the upper water (where they feed algae) and they are minimal in nitrogen and phosphates (compare analysis). Adding nitrogen to a fish tank only encourages algae. I won't go into the science to keep this brief. And the Flourish Tabs last 3-4 months.

Light is an issue, but should be correctable. The brightest light, the "daylight" period for plant photosynthesis, should be somewhere around 6 to 8 or 9 or sometimes 10 hours, but no more. We use algae problems to work this duration out. But it has to be "plant usable" light, and that is where spectrum comes in. Kelvin measures colour temperature (nothing to do with heat temp), and it is given here as 6500K to 10000K. Sunlight is in the 5000K to 6500K range. The lower the K number, the "warmer" the light, meaning more red and less blue in the wavelengths, and the higher the K the more blue and less red. Plants need red and blue, and more of the red, to photosynthesize; adding green does improve plant growth. 5000K-6500K is an ideal balance. See if you can get the K down, maybe turning off the blue LED diodes? Also, be careful with the sunrise/sunset cycles, they can really benefit algae but never plants, so keep these minimal, no more than 30 minutes each in a 24-hour cycle.

Blackouts temporarily help, but the problem comes back because this is not the crux of the problem. Nutrients/organics are, in the presence of light. This is where the fertilizers help, and light duration. You want the plants to use both, thwarting algae. Do substantial water changes, at least 50%, up to 60% once a week, at one time. Vacuum well into the substrate in open areas. Keep the filter media spotless. All of this reduces organics hopefully starving algae. Organics dissolved in the tap water can be high, remarkably so. But you need to get the organic matter out of the tank, so in the long-run it helps.

Green water is unicellular algae feeding on dissolved organics in thee presence of light. A photo of the entire tank so we can see the plants will help assessing fertilizers, etc.

 

[pondholler]

Thanks very much, Byron, for your thorough reply. I will get a photo of the tank up in the next couple of hours. Meanwhile, will try to figure out the Hygger lighting system.

 

[pondholler]

There are a few issues here, some of which you have already guessed at. To get one out of the way quickly, don't use StressZyme. While I and most consider API a leader in the hobby, they still have some products that frankly should never enter an aquarium, and this is one of them. The claims they make for this chemical concoction are beyond logic. Only two chemicals should ever go in a tank with live fish...conditioner and--if necessary--plant fertilizer. API's Tap Water Conditioner is superior because it only deals with what needs dealing with, and in detoxifying the heavy metals (some of which are essential plant nutrients) it does not use chemicals that prevent plants from taking these detoxified metals up. Liquid plant fertilizer that is comprehensive maybe, let's leave that for now because currently this will only feed the green water.

Staying with additives...NilOCG Thrive Caps don't look too bad, but they are certainly not good. Seachem's Flourish Tabs are far superior. For one thing, FT do not have nutrients that will get into the upper water (where they feed algae) and they are minimal in nitrogen and phosphates (compare analysis). Adding nitrogen to a fish tank only encourages algae. I won't go into the science to keep this brief. And the Flourish Tabs last 3-4 months.

Light is an issue, but should be correctable. The brightest light, the "daylight" period for plant photosynthesis, should be somewhere around 6 to 8 or 9 or sometimes 10 hours, but no more. We use algae problems to work this duration out. But it has to be "plant usable" light, and that is where spectrum comes in. Kelvin measures colour temperature (nothing to do with heat temp), and it is given here as 6500K to 10000K. Sunlight is in the 5000K to 6500K range. The lower the K number, the "warmer" the light, meaning more red and less blue in the wavelengths, and the higher the K the more blue and less red. Plants need red and blue, and more of the red, to photosynthesize; adding green does improve plant growth. 5000K-6500K is an ideal balance. See if you can get the K down, maybe turning off the blue LED diodes? Also, be careful with the sunrise/sunset cycles, they can really benefit algae but never plants, so keep these minimal, no more than 30 minutes each in a 24-hour cycle.

Blackouts temporarily help, but the problem comes back because this is not the crux of the problem. Nutrients/organics are, in the presence of light. This is where the fertilizers help, and light duration. You want the plants to use both, thwarting algae. Do substantial water changes, at least 50%, up to 60% once a week, at one time. Vacuum well into the substrate in open areas. Keep the filter media spotless. All of this reduces organics hopefully starving algae. Organics dissolved in the tap water can be high, remarkably so. But you need to get the organic matter out of the tank, so in the long-run it helps.

Green water is unicellular algae feeding on dissolved organics in thee presence of light. A photo of the entire tank so we can see the plants will help assessing fertilizers, etc.

Attaching two pics. One is of the whole aquarium, as requested. It doesn't really show the extent of the algae bloom, so I'm also sending a close-up of part of the tank. Thanks so much for your help.

 

[Byron]

OK, I wanted to see the plant load, wasn't concerned about the green water, I know what that is. First thing, deal with the light, as previously explained; I'm sure that unit will provide options. Second, do the W/C with good substrate cleaning, get out all of those fertilizer tabs, they are now doing absolutely nothing but feeding algae, and they are probably dissolving which the FT do not do. Third, get some substantial floating plants first. These shade the aquarium, a benefit. And they suck up incredible levels of ammonia (and other nutrients obviously), and that will help too. Then plan lower plants. I would forget stem plants and concentrate on substantial rooted plants, like swords; this large tank with all that wood is crying out for sword plants (Echinodorus species). These are heavy, heavy root feeders and will do a lot. Push one FT (Flourish Tab) next to each sword when you plant them, they are good for 3-4 months.

Floating Plants that are substantial...Water Sprite, Frogbit, or Water Lettuce. In my experience the first is the best and fastest at growing and it will produce many daughter plants that can be pulled off the frond (leaf) and used as a new plant, or tossed in the compost, whatever. Smaller plants for the substrate are pygmy chain swords (Helanthium tenellum), crypts once you feel more confident. The swords are easy plants.

 

[10 Tanks]

Hello pond. I've found that strong lighting is the problem with an algae bloom. It will take over the tank until you do a couple of things. Reduce the lighting and start the tank over. I started up a tank some time ago and thought that a strong light would help my Anubias, Anacharis and Dwarf Water Lettuce. The strong light only worked on the algae and it took over the tank. Large, weekly water changes did nothing. In the end, I reduced the light and moved all the fish. I took out the plants and cleaned them. The rocks and driftwood, I left outside in the sun. The sun dried up all that stuff and made cleaning so easy. I put it all back together and what a difference. The lower light worked for the plants and the algae hasn't returned. The tank water is clear and the tank looks so much better.

10 Tanks (Now 11)

 

[pondholler]

OK, I wanted to see the plant load, wasn't concerned about the green water, I know what that is. First thing, deal with the light, as previously explained; I'm sure that unit will provide options. Second, do the W/C with good substrate cleaning, get out all of those fertilizer tabs, they are now doing absolutely nothing but feeding algae, and they are probably dissolving which the FT do not do. Third, get some substantial floating plants first. These shade the aquarium, a benefit. And they suck up incredible levels of ammonia (and other nutrients obviously), and that will help too. Then plan lower plants. I would forget stem plants and concentrate on substantial rooted plants, like swords; this large tank with all that wood is crying out for sword plants (Echinodorus species). These are heavy, heavy root feeders and will do a lot. Push one FT (Flourish Tab) next to each sword when you plant them, they are good for 3-4 months.

Floating Plants that are substantial...Water Sprite, Frogbit, or Water Lettuce. In my experience the first is the best and fastest at growing and it will produce many daughter plants that can be pulled off the frond (leaf) and used as a new plant, or tossed in the compost, whatever. Smaller plants for the substrate are pygmy chain swords (Helanthium tenellum), crypts once you feel more confident. The swords are easy plants.

Thank you again, Byron. Everything you suggested is doable.

I have one question. A neighbor who raised and distributed tropical fish for a couple of decades before retiring told me today that what we need is a UV sterilizing unit. Do you agree that this would help? Do you have any experience with this?

 

[Byron]

Thank you again, Byron. Everything you suggested is doable.

I have one question. A neighbor who raised and distributed tropical fish for a couple of decades before retiring told me today that what we need is a UV sterilizing unit. Do you agree that this would help? Do you have any experience with this?

There is only one time that UV may be useful in freshwater aquaria, and ironically it is with green water. But it is not something I would ever do, nor recommend. For one thing, exposure to UV is carcinogenic. Second, it can work but only up to a point. If you could get all the water out of the tank and through the UV and into another tank, then it should deal with unicellular algae (and parasites that are free in the water). But otherwise, don't waste your money.

There is a reason algae is problematic, be it green water or some solid species like black brush. And it is easy to deal with the cause. No tank is algae-free, but we aim to keep it under control, and that (silly though it may sound) is actually easy to do. You just need to get the light/nutrient balance established (or re-established) for the plant species and number.

I'll give an illustration on how delicate this balance sometimes may be. I dealt with black brush algae for several years. Not bad, but it was there, only in some tanks, never others. After a couple of years, I worked out the balance to seven hours of tank lighting each day, using a timer so it was consistent. This worked fine during the winter months, but in the summer the algae increased. It finally hit me the second year this happened that it was the additional daylight in summer, both the stronger intensity and the longer duration. I completely blackened out the windows (in a fish room this was easy to do), and end of problem algae. For six years after it never increased at any time. I had found the balance, taking into account my moderate lighting, the fish load, and the plant species and number.

I would never suggest tearing the aquarium down for this, it is nature being nature and we simply have to recognize it and use nature to combat it.