what is the size of your tank? depth height?
it could be alot of stuff and flow rate, volume of co2, quality of water, how long has the plant been put into your tank. if they are new plant, you need to wait for the plant to get used to your water quality.
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i have a 18" tank. i use a 2215 which have little bubble. then, i use a 2217 eheim, which makes lot of bubble. i am using 1 bubble/sec. if you ask me why flow rate make more bubble, i don't know... haha. if your tank isn't too tall, then many brothers here will suggest 水草店t8 15wx4 燈箱 with ada tube and that's what i bought. what tube you are using? to save money, you may try philips tube for 3x/each first and see.
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i am new hand only and can share with you for my little experience and from what i read from the previous post here.
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just take my word for reference and don't trust too much as i am new hand. you better wait for the expert to reply.
its much easy for other expert to help you if you list out all your details, as tank size, lightering & co2 period, brand or k of light tube etc.
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they are helpful and willing to teach. that's the way i learn most of my stuff and not waste money for a wrong equipement.