Fluval Spec V - am I doing this right?

[Kozik]

Hi everyone,

I have been a freshwater guy for over 2 years currently running 4 tanks, at my peak 6. Always interested in saltwater so I decided to pick up a spec v and set it up for saltwater.

Currently Here are the specs:
Hardware:
- Stock spec v filter (no mods)
- charcoal/fluva bio media in the bottom
- chemi pure elite at the top
- stock spec v light
- hydor Koralia nano 240 (top right pointing front middle slightly down)
- hydor 50w heater in the fluval filter part

Livestock/Other:
- About 5lbs caribsea arag alive
- just over 6lbs live rock
- 2 Nausarious snails
- 1 Asterea snail
- 1 Cerith snail (bought 2 but one was empty)
- 1 Cleaner shrimp

I do a weekly water change as I do with all my other tanks every Saturday, I'm religious about this I never miss it (my wife hates this). On this tank I empty about 20-30% and the. In a bucket I fill with RO water and mix with Instant Ocean Reef Crystal to get the tank to about 1.025 on an ATC refractometer and then I fill the tank.

So here's why I'm not sure I'm doing things right, I'm getting a ton of algae. Green Algae, purpleish algae, and brown algae you name it I've got it in abundance (I know there are lots more types of algae I don't have). My light is on a timer 7:30-4 so about 8:30 hours and from what I understand this light is fairly weak compared to a normal saltwater light.

What am I doing wrong?

[ssick92]

How old is the tank? The algae could be for a lot of different reasons. The most common being high phosphate and nitrate in the tank, which is usually caused by overfeeding, though can also be caused by using rock that leeches these compounds into the tank which is then used by the algae, or poor source water. My guess is that the purple algae you are seeing is cyanobacteria which needs high nutrients (nitrate) and low flow.

Other reasons could be poor lighting. What kind of lighting do you have over the tank? If the bulbs are old and have shifted off-spectrum it can facilitate algae growth. This is also the case if the tank gets hit by natural sunlight through windows -- the windows and tank glass shift the light spectrum which then can facilitate algae growth as well.

My guess is that your source water is introducing unwanted nutrients into the tank. Are you running just RO water, or RODI? If you don't have the DI stage in your filtration you will be introducing unwanted contaminants into your tank which sometimes can lead to algae issues (typically phosphate). Do you have a TDS meter to measure the TDS of your source water before you mix the salt? You will want the TDS to be absolutely 000 -- most people replace their filters once they are getting 001-002 TDS, and without a DI resin as part of your filtration you are probably upwards of 010 TDS.

[Kozik]

How old is the tank? The algae could be for a lot of different reasons. The most common being high phosphate and nitrate in the tank, which is usually caused by overfeeding, though can also be caused by using rock that leeches these compounds into the tank which is then used by the algae, or poor source water. My guess is that the purple algae you are seeing is cyanobacteria which needs high nutrients (nitrate) and low flow.

The tank is only a few months old, I'm using Fiji rock from my lfs. I don't think flow is the problem because shouldn't the Koralia 240 be more than enough?

Other reasons could be poor lighting. What kind of lighting do you have over the tank? If the bulbs are old and have shifted off-spectrum it can facilitate algae growth. This is also the case if the tank gets hit by natural sunlight through windows -- the windows and tank glass shift the light spectrum which then can facilitate algae growth as well.

The light is just the stock spec v light it seem like a standar led light meant for freshwater tanks. The tank does get natural sunlight, when the lights are off I generally stick a black Tshirt over the tank but during the day the natural light is hitting it. Not sure if I can stop this... any suggestions other than move the tank?

My guess is that your source water is introducing unwanted nutrients into the tank. Are you running just RO water, or RODI? If you don't have the DI stage in your filtration you will be introducing unwanted contaminants into your tank which sometimes can lead to algae issues (typically phosphate). Do you have a TDS meter to measure the TDS of your source water before you mix the salt? You will want the TDS to be absolutely 000 -- most people replace their filters once they are getting 001-002 TDS, and without a DI resin as part of your filtration you are probably upwards of 010 TDS.

Not sure if it's RO or RODI, I get the water from my parents house which has a whole home unit :S don't have a TDS meter but I'll get on that one.

[Reeferman1019]

my Fluval spec v leaked after a month and had to upgrade to a standard 10G tank...what I did was removed the stock filter sponge it's a nitrate factory...I pit some rubble rock in the back and a bag of purigen on top. As for flow I would get a jeabo rw4 and stick it in the back of the tank in the middle facing forward. With these small tanks you have to feed less and keep up with WCs. You can try to get a AI Prime and run that light. Algae is probably coming from LR, and the tank being new. I would always use RODI water


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[ssick92]

The tank is only a few months old, I'm using Fiji rock from my lfs. I don't think flow is the problem because shouldn't the Koralia 240 be more than enough?

Ya, it should be more than enough gph wise, but if I remember correctly those koralias direct their flow pretty unidirectionally (that's a word right?). In other words, it may be plenty of flow in the middle of the tank, but when you drop some food pellets in the tank do you notice the food congregating to the same areas of the tank on the sandbed, or does it typically remain in the water column for a bit? The tank may still have some low flow areas even though that powerhead is technically giving you enough gph.

The light is just the stock spec v light it seem like a standar led light meant for freshwater tanks. The tank does get natural sunlight, when the lights are off I generally stick a black Tshirt over the tank but during the day the natural light is hitting it. Not sure if I can stop this... any suggestions other than move the tank?

If it is LED then it won't cause your algae issues, but it might not be sufficient for growing higher light demanding corals (LPS, SPS), but that is another issue.

Not sure if it's RO or RODI, I get the water from my parents house which has a whole home unit :S don't have a TDS meter but I'll get on that one.

If it is the same water that is hooked up to your family drinking unit, this is probably your issue. It will not include a DI resin stage of filtration because it widely considered "bad" to drink water after it has been deionized via a DI resin (an argument in and of itself). You could insert a T in the line after your family's RO membrane and send a portion of the water through a DI resin to only use for your tank. You could put a ball valve on it so it will only divert water when you want it to.

What is your nitrate level in the tank currently? Do you have a high quality test kit like the Salifert or Hanna checker tests to monitor it? Generally you will want to keep it below 10ppm, and based on your water change schedule this should be no problem, unless your source water is introducing additional nutrients.

[Kozik]

So sounds like rodi water is my problem (lack of) anything you guys that won't break the bank?

Is this thing any good?
https://www.amazon.ca/Aquatic-Changing-Deionization-Cartridge-50-Gallon/dp/B00204CQF6