Coral Help

[cybanez]

I’m new to the reef world and my first couple corals won’t open up. My water chemistry isn’t super stable but I’m checking it daily to make sure I can adjust if needed.
I don’t know what else to do but worry I’ll end up losing them.

It’s a Fluval Evo 13.5. Stock lights.

 

[kingranch2003]

Hello! How old is your tank, and what is your P04? I see that you're running chemipure. Let's make sure you're not striping all nutrients. Do you have fish?
Let's talk this out.

 

[Mr. Mojo Rising]

What are your nitrate and phosphate levels? What test kit are you using? How old is the tank? How long have these corals been in your tank?

 

[cybanez]

Hello! How old is your tank, and what is your P04? I see that you're running chemipure. Let's make sure you're not striping all nutrients. Do you have fish?
Let's talk this out.

Thank you! I set it up on 8/23 and added the corals on 9/23. I just got a Watchman Goby last week but he doesn’t go anywhere near the corals.
I’ve dosed them with microvert for food but otherwise I haven’t added any minerals.

PO4 is 0 mg/L

I appreciate the help!!

 

[JumboShrimp]

(I'm more of a fish-guy than a coral-guy, but you will get excellent advice here on R2R!)

 

[BryanM]

Tons of good info here on getting started.

https://www.reef2reef.com/threads/the-supreme-guide-to-setting-up-a-saltwater-reef-aquarium.138750/
Lack of nutrients (Nitrates and Phosphates) is never good in our systems. Nitrates 5-20, phos .1-.3 are good targets.

It is false to think that lack of these things will produce little to no algae... It is often quite the opposite, it will cause all sorts of nuisance algae issues.

And corals need both to thrive.

 

[cybanez]

Tons of good info here on getting started.

https://www.reef2reef.com/threads/the-supreme-guide-to-setting-up-a-saltwater-reef-aquarium.138750/
Lack of nutrients (Nitrates and Phosphates) is never good in our systems. Nitrates 5-20, phos .1-.3 are good targets.

It is false to think that lack of these things will produce little to no algae... It is often quite the opposite, it will cause all sorts of nuisance algae issues.

And corals need both to thrive.

Thank you! I honestly thought I was shooting for 0 for both! I’ll take out the chemipure and see what I can find at Petco for an additive until I can get to a LFS this weekend!

I will read up on what you sent. Honestly I get frustrated when I start reading all the guides because half of them contradict the other half!

 

[TheNative192]

Thank you! I honestly thought I was shooting for 0 for both! I’ll take out the chemipure and see what I can find at Petco for an additive until I can get to a LFS this weekend!

I will read up on what you sent. Honestly I get frustrated when I start reading all the guides because half of them contradict the other half!

Key Parameters to Focus On:
The two most important parameters right now are Nitrate and Phosphate.

If you’re using the API test kits, just keep in mind they’re not very precise — especially for Phosphate. The API range doesn’t even include the ideal values we aim for (around 0.05–0.2 ppm). For now, if your phosphate test isn’t bright yellow (a slight blue tint is okay), you’re probably in a safe range.

For more accurate testing, consider Salifert test kits or Hanna Checkers — both are much better for reef parameters.

---

About the Hammer Coral:
It’s probably a bit early to add a Hammer to a one-month-old tank. They need stronger flow and more light than what the stock Fluval Evo provides. It should be as high up in the tank as possible and aim the nozzle towards it but not directly at it. Try to bounce the flow around the tank but it is way too low as the stock light may barely sustain it

I have a Fluval myself — the lid is great for reducing evaporation, but the lighting is definitely on the weak side. Between the low light and limited flow, that’s likely why your Hammer isn’t opening fully.

Also, make sure you have a heater and that your temperature stays stable. Corals don’t like temperature swings.

---

Ideal Water Parameters:

• Alkalinity: 8–12 dKH (change slowly)
• Calcium: 400–420 ppm (change slowly)
• Magnesium: 1350–1400 ppm (requires a separate test kit if you’re using API)
• pH: 8.0–8.4 (change slowly)
• Nitrate: 5–15 ppm (generally 20–100× your phosphate level)
• Phosphate: 0.05–0.2 ppm (higher values = more algae)
• Salinity: 1.024 (let evaporation bring it up to 1.025–1.026, but avoid above 1.026)
• Temperature: 77–78°F

If your salinity is high, remove a small amount of tank water and replace it with RODI water to bring it down gradually. Natural sea water is 1.026 but if it goes above that number then it is bad. If you get an automatic water top off then 1.026 is fine but until then slowly lower it to 1.024 or 1.025. Fish will accept 1.022 to 1.026 Corals like 1.024 to 1.026.

 

[cybanez]

Key Parameters to Focus On:
The two most important parameters right now are Nitrate and Phosphate.

If you’re using the API test kits, just keep in mind they’re not very precise — especially for Phosphate. The API range doesn’t even include the ideal values we aim for (around 0.05–0.2 ppm). For now, if your phosphate test isn’t bright yellow (a slight blue tint is okay), you’re probably in a safe range.

For more accurate testing, consider Salifert test kits or Hanna Checkers — both are much better for reef parameters.

---

About the Hammer Coral:
It’s probably a bit early to add a Hammer to a one-month-old tank. They need stronger flow and more light than what the stock Fluval Evo provides. It should be as high up in the tank as possible and aim the nozzle towards it but not directly at it. Try to bounce the flow around the tank but it is way too low as the stock light may barely sustain it

I have a Fluval myself — the lid is great for reducing evaporation, but the lighting is definitely on the weak side. Between the low light and limited flow, that’s likely why your Hammer isn’t opening fully.

Also, make sure you have a heater and that your temperature stays stable. Corals don’t like temperature swings.

---

Ideal Water Parameters:

• Alkalinity: 8–12 dKH (change slowly)
• Calcium: 400–420 ppm (change slowly)
• Magnesium: 1350–1400 ppm (requires a separate test kit if you’re using API)
• pH: 8.0–8.4 (change slowly)
• Nitrate: 5–15 ppm (generally 20–100× your phosphate level)
• Phosphate: 0.05–0.2 ppm (higher values = more algae)
• Salinity: 1.024 (let evaporation bring it up to 1.025–1.026, but avoid above 1.026)
• Temperature: 77–78°F

If your salinity is high, remove a small amount of tank water and replace it with RODI water to bring it down gradually. Natural sea water is 1.026 but if it goes above that number then it is bad. If you get an automatic water top off then 1.026 is fine but until then slowly lower it to 1.024 or 1.025. Fish will accept 1.022 to 1.026 Corals like 1.024 to 1.026.

This is amazing!!! Thank you!

I’ve got some work to do but will get this moving forward.

Do you have a recommendation for an upgraded light? I swear I read up on each coral before I bought them and bubble coral said low to medium flow and medium light intensity, or else I wouldn’t have bought it. I’ve tried to be very careful about research before I add anything so I’m not just killing livestock.

 

[kingranch2003]

@cybanez I couldn't agree more with the information provided above. Zero nutrients isn't the goal, healthy thriving corals are. You're right that there is conflicting information. You did the right thing by reaching out to the forum. Speak with real reefers and see what has worked for them over a fair amount of time.

 

[TheNative192]

This is amazing!!! Thank you!

I’ve got some work to do but will get this moving forward.

Do you have a recommendation for an upgraded light? I swear I read up on each coral before I bought them and bubble coral said low to medium flow and medium light intensity, or else I wouldn’t have bought it. I’ve tried to be very careful about research before I add anything so I’m not just killing livestock.

So, the tricky part of your tank is that the lid is built-in with the light. As you mentioned, you have a goby, so it’s crucial to always have a lid and avoid leaving even the slightest crack, as they’re massive jumpers.

If you remove the lid, be prepared for significant evaporation. If the tank sits at 1.026, it could jump up to 1.028, stressing or killing everything overnight without a lid or automatic top-off. Personally, I prefer Gravity-fed ATOs with a float valve, which are also affordable and help stabilize the tank significantly.

Now, regarding lights, they tend to be quite expensive. The AI Prime 16 HD is a light that you might be able to find secondhand. I know many people have had success growing all types of corals in their Fluval evo tanks with it. It usually is $100-150 second hand though. Also if you do get this light, you should keep it at least 10 inches away from the water and feel free to ask about settings later.

If you’re on a budget, I recommend the Hygger 30 watts marine light from Amazon. It may not last forever, but it actually has very good PAR readings. I would keep it on setting 3/5 all blues or 4/5 all blues, about six inches above the water. I have one on a 11 gallon cube tank and it grows corals like crazy. It’s also $32. It may not last forever or be a long term solution but it is a great option.

Again, don’t leave the lid off overnight, or the goby will jump. If you use a different light, you’ll need a different lid, and there may be some 3D printed options available on Etsy. Lids unfortunately can be expensive when done well by someone like Kracken Lids so I would say stick with an Etsy lid.

In the meantime, even if you have to reglue it, move the hammer coral up in the tank. The zoas will be fine where they are. Next, when you buy new corals, focus on soft corals, as they’re easier to care for. Once you get the hang of those, move up to LPS corals (next level, which includes the hammers) The highest level are SPS corals which I would say you need a different tank or a lot of experience to handle those.

Most importantly do not get discouraged if something doesn’t make it. It is a learning experience and I do not doubt Petco likely gave you bad advice to start. The key thing to remember is it’s their job to sell you a product so use the forum, google, so that way you have the tools and knowledge to improve. My fluval tank has Green star polyp and pulsing Xenia which many do not like because it grows like weeds but it honestly looks great and after my success there I got a larger tank with all crazy corals too so key thing is don’t get discouraged and ask questions!

 

[cybanez]

So, the tricky part of your tank is that the lid is built-in with the light. As you mentioned, you have a goby, so it’s crucial to always have a lid and avoid leaving even the slightest crack, as they’re massive jumpers.

If you remove the lid, be prepared for significant evaporation. If the tank sits at 1.026, it could jump up to 1.028, stressing or killing everything overnight without a lid or automatic top-off. Personally, I prefer Gravity-fed ATOs with a float valve, which are also affordable and help stabilize the tank significantly.

Now, regarding lights, they tend to be quite expensive. The AI Prime 16 HD is a light that you might be able to find secondhand. I know many people have had success growing all types of corals in their Fluval evo tanks with it. It usually is $100-150 second hand though. Also if you do get this light, you should keep it at least 10 inches away from the water and feel free to ask about settings later.

If you’re on a budget, I recommend the Hygger 30 watts marine light from Amazon. It may not last forever, but it actually has very good PAR readings. I would keep it on setting 3/5 all blues or 4/5 all blues, about six inches above the water. I have one on a 11 gallon cube tank and it grows corals like crazy. It’s also $32. It may not last forever or be a long term solution but it is a great option.

Again, don’t leave the lid off overnight, or the goby will jump. If you use a different light, you’ll need a different lid, and there may be some 3D printed options available on Etsy. Lids unfortunately can be expensive when done well by someone like Kracken Lids so I would say stick with an Etsy lid.

In the meantime, even if you have to reglue it, move the hammer coral up in the tank. The zoas will be fine where they are. Next, when you buy new corals, focus on soft corals, as they’re easier to care for. Once you get the hang of those, move up to LPS corals (next level, which includes the hammers) The highest level are SPS corals which I would say you need a different tank or a lot of experience to handle those.

Most importantly do not get discouraged if something doesn’t make it. It is a learning experience and I do not doubt Petco likely gave you bad advice to start. The key thing to remember is it’s their job to sell you a product so use the forum, google, so that way you have the tools and knowledge to improve. My fluval tank has Green star polyp and pulsing Xenia which many do not like because it grows like weeds but it honestly looks great and after my success there I got a larger tank with all crazy corals too so key thing is don’t get discouraged and ask questions!

Thank you again!! I really do appreciate you and the others encouraging using the forum. I was a bit hesitant as I know some of the other forums out there are full of jerks just wanting to criticize people for not knowing enough. The last thing I want is discouragement as I want to do this right and build a great tank .

I’ll definitely move the coral up and look at a light upgrade. I do wish there were more options for the lid available. I’ve seen a couple on Etsy but wasn’t in love with any of them.

Thank you again for the encouragement!! I’ll follow up with the changes and results.

 

[BryanM]

I was a bit hesitant as I know some of the other forums out there are full of jerks just wanting to criticize people for not knowing enough

Best part of this forum is the almost 100% absence of this. It is here, sometimes, and it gets squashed pretty quickly.

Most of us know this hobby is HARD.