# Any Experience with Fluval Flex 9 or 15? Substrate Recommendations?



## Melogrunty (Sep 15, 2020)

My current tank is Amazon.com : hygger Horizon 8 Gallon LED Glass Aquarium Kit for Starters with 7W Power Filter Pump, 18W Colored led Light, Wide View Curved Shape Fish Tank with Undetachable 3D Rockery Background Decor : Pet Supplies
I'm gonna cut my losses and go with a new tank. Even though my water parameters are fine (posted a few times in different threads), the 3D mountains for this tank are building up a bunch of green and brown gunk even after I vacuum them each week with scrub attachment during water change. Also, the part under the mountains is near impossible to clean.

I was hoping someone had a positive experience with either of the Fluval tanks I mentioned. I will just be housing my single Betta fish for now but may add a couple friends later down the line, once he adjusts for a handful of months. If anyone could give feedback that would be great. If I just have the Betta, would 9 be enough? 

Any substrate recommendations? Preferably something lighter colored if possible and something that could do well with beginner plants like Anubias Nana and Moss Balls and maybe something else that's low maintenance.

Thanks very much!


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## RussellTheShihTzu (Mar 19, 2013)

How long do you leave your lights on? Is the tank near a window? I finally had to get a timer or I would forget to turn them off after eight hours. Otherwise, algae.

Do you have sand substrate? If so, it could be brown diatoms which are common in new tanks. Diatoms eventually go away once the silicates in the sand are depleted as that's their main source of nourishment.

I'm not a fan of kits but the filter in that tank is good for a 10 gallon; they require GPH of 50+; a 15 is 75 GPH; a 20 around 90. The current filter has a GPH of 110. I'd suggest that instead of a kit you get an empty tank and use your current equipment. If you already have a heater of at least 50 watts and a thermometer all you would need is a canopy. Those run around $10. Often you can find 10+ gallon tanks on Craig's List for next to nothing; or, in Goodwill. But get the biggest tank for which you have room. 

You can also add a second filter. I try to run two so if one conks out I have a reserve. My husband doesn't believe me, though. He says it's so if I get yet another tank I don't have to cycle the filter. Can you believe it????

Minimum for a community tank is one that is at least 24" wide and 11" deep so at least a 10 My preferred size for Betta-based community tanks is a 20 long which is 30" x 12" x 12". Most suitable Betta tank mates are small, shoaling fish; they need a longer footprint for swimming. You will also need a shoal of at least six but 10 is better. A 10 can hold two shoals _if_ you get mid- and bottom-dwellers. Overcrowding is when you have too many fish that occupy the same level. For a 20.

I prefer sand substrate. You can use a plain piece of airline tubing as a siphon/vacuum. Tubing is much easier to maneuver around plants, too. All you do is hover the tube slightly above the sand. Being narrow, it will suck up a lot of stuff pretty fast.

So, FWIW, that's my opinion and advice. We do have a Fluval owner thread if you want to check it out. I believe it's in this sub-forum.


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## Melogrunty (Sep 15, 2020)

I was leaving the light on about 12 hours per day. Is it best to only leave it on for about 8? No direct sunlight, it's on my kitchen with no access to sunlight. 

I have gravel substrate but I want to use sand with my new tank. Do you think this 



 is a good way to clean sand instead of rinsing it in buckets?

My current tank has only a sponge and carbon filter (don't have the carbon attached currently). The heater is only 25W. The Fluval 15 tank I'm getting has a much better filter system and 50W heater.

My counter only has room for a 19" wide tank. The tank I'm going to be getting is 16x15x15. I feel bad it's so tall for a betta but I'll be adding some Betta hammocks and trying to find a really tall grass plant (have any suggestions?) so he can nap closer to the surface. I won't have any fancy CO2 for the plants but I'll be using Seachem Flourish, which I've read that it feeds plants but keeps algae under control.

Thanks very much for all the advice and taking the time to respond!


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## RussellTheShihTzu (Mar 19, 2013)

I've not cleaned sand that way but I've heard others say it worked quite well.

Don't worry that the tank is tall. As long as it is filtered and oxygenated Betta do not need to use their labyrinth. They are facultative breathers so the labyrinth is their secondary breathing organ after their gills. That they don't do well in taller tanks is more Internet hooha that is not based in fact but in "logic." 

Try turning the lights on for eight hours-only first. If you are referring to Flourish _Excel_, it is not a fertilizer but supposed to be a carbon source. It will kill algae but it will also kill certain aquarium plants. SeaChem will admit it kills Anacharis. Have you already purchased?

Any tall stem plant will do if you're looking for a Betta rest. I have tall Anubias, Cryptocoryne, Hornwort, Cyprus and Swords.

Always glad to help.


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## Melogrunty (Sep 15, 2020)

This one is just regular Flourish and not Excel thankfully. Thanks for the plant recommendations!


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## Melogrunty (Sep 15, 2020)

It arrived broken


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## RussellTheShihTzu (Mar 19, 2013)

So sorry. I had that happen once and know exactly what it's like.


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