S. Repens melted after adding CO2

This is my first heavily planted aquarium so I'm not really experienced with how to balance the tank.

Tank info:
20 gallon tank 15inch tall, Nicre BrightLED (7500K 18W, PAR about 100-150? not sure on this) 8hrs a day, Ammonia/NO2/NO3 all 0, PH 6.5-7. Tropica aqua soil+Tropica premium nutrition. There are 8 pea puffers and 6 ghoast shrimps(intended to be food but puffers didn't touch them) and lots plants.

Everything was doing great until I bought the Fluval Mini CO2 kit, which instead of bubble counts, it fills the 2 air chambers in the tank and then absorbed by the water, so I assume the water is saturated with CO2. Here's a link to the kit in case anyone is curious: Fluval Mini Pressurized 20g-CO2 Kit - 0.7 Ounces: Amazon.ca: Pet Supplies

I had the S. repens for about a month before I added CO2 and it was doing so good, about 2 days after I added CO2, the plant that was closest to the CO2 chamber started to melt, so I moved it to the other side of the tank but that didn't stop it from melting. The plants near the melted one also started melting after I moved the stem to that area.

There were no melting on any other plants, is it a disease or simply plants trying to adapt new environment? Should I get rid of the melted stems to stop spreading or just leave it? Could it be a nutriant deficiency? The hair algea on Amazon sword's leaves and green algea on the side of the tank grown like crazy after I added CO2, but I don't really know if I need to dose more fert or change the light.

 

8 pea puffer is too much. Maybe lose one. Definitely lose a lot more if the tank isn't heavily planted. There are some good diy co2 kits on Amazon if you think the kit is the problem. Also check your Ph. co2 lowers your ph. You might invest in a drop checker. Make sure you have enough plants to use up the co2. Since any that aren't used may go to algae growth. Check with other people. Always good to have multiple opinions.

 

8 pea puffer is too much. Maybe lose one. Definitely lose a lot more if the tank isn't heavily planted. There are some good diy co2 kits on Amazon if you think the kit is the problem. Also check your Ph. co2 lowers your ph.

Thank you for the reply but it wasn't helping.

The puffers formed a hierarchy already, they take turns to eat. Losing any of them will cause chaos. My tank is currently covered in 8 different types of plants and the ammonia/NO2/NO3 is always zero so I don't see why you may think the stocking is an issue.

If you ever had puffers before you would know how much snail shells it has left to act as natural ph buffer, so CO2 helps maintain the PH to around 7. I do think my tank may have too much calcium from the shells, but I don't really know if that's the reason of algae or how to remove them.

 

I have never tried to grow s. repens, but as a carpeting plant, it needs high lighting, CO2 injection and proper fertilization. With a 20 gallon high tank, a 18 watt light only represents 0.9 watts per gallon, which would not be considered high lighting. I have a 26 watt Hygger HG-957 light on a 10 gallon tank. That does provide high lighting. To provide high lighting on a 20 gallon high tank, I would suggest a 24" long, 36 watt light. That is twice the lighting you currently have on your tank.

What is the pH and dKH in your tank? If the CO2 dropped the pH below the level acceptable for the plants, that could cause an issue.

 

I have never tried to grow s. repens, but as a carpeting plant, it needs high lighting, CO2 injection and proper fertilization. With a 20 gallon high tank, a 18 watt light only represents 0.9 watts per gallon, which would not be considered high lighting. I have a 26 watt Hygger HG-957 light on a 10 gallon tank. That does provide high lighting. To provide high lighting on a 20 gallon high tank, I would suggest a 24" long, 36 watt light. That is twice the lighting you currently have on your tank.

What is the pH and dKH in your tank? If the CO2 dropped the pH below the level acceptable for the plants, that could cause an issue.

The PH was 6.5-7, towards the 7 end, as the leftover snail shells provides natural ph buffer.

I did consider buying a second light but I just don't understand why it was doing so good before adding CO2, and how adding something that is supposed to be beneficial makes them worse.

 

Thank you for the reply but it wasn't helping.

The puffers formed a hierarchy already, they take turns to eat. Losing any of them will cause chaos. My tank is currently covered in 8 different types of plants and the ammonia/NO2/NO3 is always zero so I don't see why you may think the stocking is an issue.

If you ever had puffers before you would know how much snail shells it has left to act as natural ph buffer, so CO2 helps maintain the PH to around 7. I do think my tank may have too much calcium from the shells, but I don't really know if that's the reason of algae or how to remove them.

Yeah you’re good on the amount of puffers in your tank you don’t need to get rid of one. And maybe it’s the sudden change? Because even though Co2 helps plants if they have never had it before it might have shocked them but they will bounce back. This is just a theory though

 

If your going to run co2 you need to be dosing ferts. You have a passive system. I have no personal experience with that type but have seen other individuals that have great success.
A great all in one fert will be the Nilocg Thrive line, they have different mixes based on your tank.
I would probably try to leave the S. Repens and see if they come back, they may just be adjusting. Its also possibly lack of ferts if they have been in the tank for 2 months. Co2 seems to speed up the process of thriving or dying if all conditions are not met. I recently got a nicrew skyled for my 5.5g tank and I'm impressed with their product. Your light is just fine.
I would probably get a good all in 1 fert and start your light at a 6hr running time. Once dosing ferts and algae under control start increasing your light by 30mins-1hr but give the plants a week or 2 to respond and see if algae develops. Green hair and dust algae is the easiest to get rid of, the dust algae is also typical with a bright light with high intensity.

 

Your NO3 is 0? In my opinion this is not so good for a planted tank. Your plants may be starving. Add some nitrogen and see if it helps.

 

If your going to run co2 you need to be dosing ferts. You have a passive system. I have no personal experience with that type but have seen other individuals that have great success.
A great all in one fert will be the Nilocg Thrive line, they have different mixes based on your tank.
I would probably try to leave the S. Repens and see if they come back, they may just be adjusting. Its also possibly lack of ferts if they have been in the tank for 2 months. Co2 seems to speed up the process of thriving or dying if all conditions are not met. I recently got a nicrew skyled for my 5.5g tank and I'm impressed with their product. Your light is just fine.
I would probably get a good all in 1 fert and start your light at a 6hr running time. Once dosing ferts and algae under control start increasing your light by 30mins-1hr but give the plants a week or 2 to respond and see if algae develops. Green hair and dust algae is the easiest to get rid of, the dust algae is also typical with a bright light with high intensity.

Thank you! I dose the Tropica all-in-one Micro once a week after water change, maybe I need some macros?

Your NO3 is 0? In my opinion this is not so good for a planted tank. Your plants may be starving. Add some nitrogen and see if it helps.

I know! I don't understand why my NO3 is zero either! I once left the tank for 2 weeks without water change and the NO3 is still zero. I'm considering dose some macros but will that promote algae?

 

Plants would much rather use ammonia as a food source rather than nitrates. It may be that you have no nitrates in your tank because the plants are grabbing the ammonia before the bacteria can convert it. However, if you continue to have low nitrate levels, you can always use a nitrogen fertilizer in the tank. That could be something as simple as potassium nitrate or it could be a fertilizer that contains urea.

 

As LeviS was saying, you'll definitely need a comprehensive source of nutrition. Your plants are likely lacking macros, which are an important part of plant health. An all-in-one fert like Thrive by NilocG or APT Complete by 2Hr Aquarist is perfect for your type of aquarium.

 

For good growth plants need a proper balance of light, carbon dioxide, macro nutrients, and micronutrients. If you provide some of the needs, but not others, the plants will respond poorly. You need to figure out which factor is limiting growth and fix it.

 

Hello I had an s repens carpet that grew amazing for about the first month or two and then it randomly all started melting away to nothing one day! I didn’t add co2 but s repens seems to randomly start melting for a lot of people! I eventually gave up on it! It does good in my other tank though and never melts! Ive been wanting to give co2 a try but I’m nervous about spending the money and then my fish tank turning into a disaster!!!

 

If your going to run co2 you need to be dosing ferts. You have a passive system. I have no personal experience with that type but have seen other individuals that have great success.
A great all in one fert will be the Nilocg Thrive line, they have different mixes based on your tank.
I would probably try to leave the S. Repens and see if they come back, they may just be adjusting. Its also possibly lack of ferts if they have been in the tank for 2 months. Co2 seems to speed up the process of thriving or dying if all conditions are not met. I recently got a nicrew skyled for my 5.5g tank and I'm impressed with their product. Your light is just fine.
I would probably get a good all in 1 fert and start your light at a 6hr running time. Once dosing ferts and algae under control start increasing your light by 30mins-1hr but give the plants a week or 2 to respond and see if algae develops. Green hair and dust algae is the easiest to get rid of, the dust algae is also typical with a bright light with high intensity.

Would heavy fertilizing be necessary in deep organic substrates? I am pretty sure there are enough minerals (and a bit of carbon, occasional bits of dried grass) to supply my plants for awhile, capped under all that gravel and sand. I'm in new territory lol (I ordered my first c02, hoping my land garden instincts will kick in, I didn't realize how intimidated I was by growing decent aquatic plants until I got over that hump and dove in).
How much I have learned here!
PS that's the c02 kit I'm ordering, it's marked down from about 45 to 33 (although by the reviews not long ago it was 20ish, lol). Wish me luck not melting my plants!

 

Would heavy fertilizing be necessary in deep organic substrates? I am pretty sure there are enough minerals (and a bit of carbon, occasional bits of dried grass) to supply my plants for awhile, capped under all that gravel and sand. I'm in new territory lol (I ordered my first c02, hoping my land garden instincts will kick in, I didn't realize how intimidated I was by growing decent aquatic plants until I got over that hump and dove in).
How much I have learned here!
PS that's the c02 kit I'm ordering, it's marked down from about 45 to 33 (although by the reviews not long ago it was 20ish, lol). Wish me luck not melting my plants!

Land gardening is relatively easy. The plants have access to lots of light, many times greater than that of the most brilliantly lighted aquarium. The plants have access to an average of 410 ppm CO2 in air vs only 30 ppm maximum in water. And the plants have access to nutrients from the soil, which can be several inches to many feet thick. The challenge for land plants is to get water, especially in arid areas. However, even with soil as the substrate, we often fertilize our plants. A landscape company fertilizes my lawn five times a year. I grow containers of herbs and use a dilute solution of Miracle Grow each time I water my plants. They grow splendidly.

You probably have sufficient lighting to grow floating plants, but you need a lot more light to penetrate to the bottom of your tank where your carpeting plants grow.

Providing a layer of dirt as part of the substrate will help provide nutrients for a while. However, those nutrients will become exhausted over time and will need to be supplemented with root tabs or liquid fertilizers. There are lots of different fertilizers for aquariums, just as there are lots of different fertilizers for land plants. The aquarist has to determine the proper fertilizer and dosing frequency for fertilization, just like a land gardener.

Plants do need CO2 as one of the basic nutrients for growth. However, the plants can only use CO2 if they are getting sufficient light and other nutrients as well.

You mentioned you had snail shells in the tank. Do you still have any live snails and if so, so you wish to keep them. Snail shells are comprised primarily of calcium carbonate. At acidic pH levels, the shells will dissolve. Snails need alkaline pH levels and calcium supplementation to thrive. You can maintain the alkalinity of your water through the addition of sodium bicarbonate (baking soda). It will react with the acids in your tank to release carbon dioxide. You can use crushed coral to supplement both calcium and magnesium levels in the tank or use cuttlebone (found in the bird section of the pet store) to supplement calcium alone.

 

Thank you guys so the problem is lack of macro, guess puffers alone didn't provide enough nutrients. I was worried about adding ferts because I don't want algae outbreak, but luckily it didn't happen. I use Tropica specialized fertilizer which contains NPK as well as micros, still playing around the amounts every week for my tank.

Those melted S. repens hasn't come back yet but at least the other ones didn't melt so that's good news! Hopefully they'll carpet one day, I really like them!