wc %

[Sandnukka15]

I currently have a 65 with a 20 long sump 75 lbs of live rock and a skimmer that's rated for 75 gallons .... Current inhabitants are

5 certhis snails
1 emerald crab
1 chocolate chip starfish
2 clowns
1 firefish
1 grammar basslet
1 cardinal

Sand bed is 1-2 inches

Salinity is 1.023

Return pump 350 gallon per hour

What's a good water change percentage for this tank a week?

 

[Bent]

some things I may point out that arent releated to your question.

Your SG is a tad low. It may or may not harm future inhabitatants depending on how stable you keep it, but some more sensitive animals want 1.026.

That chocolate chip starfish needs to get put in a blender. It is a fish eater. The firefish is especially vunerable since they like to sleep on the ground.

The emerald crabs are also hit or miss when it comes to being fish killers too when they get older. Many people have had to evict their larger ones after they had one start unscrewing fish heads.

I would also argue that your return pump volume is not enough. The general Rule is 10x tank turnover per hour. So 65 gallons minus about 10 gallons of displacement for rock and sand is about 55 gallons. 55x10 is 550. So I would go on the safer side and go with an even 600. You need to get new water to the skimmer quicker, and tank turnover is the only way to do it. It will be more efficient.

But to your actual question. I do 10% per week for mine, but it all depends on your bioload and how much nutritents you are trying to export and how much of your trace elements you are trying to replenish.

 

[Sandnukka15]

Thanks for the info .... I thought most of the current group I had liked sg between 1.020-1.025?.... I'll try to slowly raise it .... What should I raise it to 1.026?

I will eventually find the chocolate chip starfish a new home then

My emerald crab is very tiny so hopefully I will be good for a while

Also I read on here that around 5x turnover is good to give the skimmer in the sump enough time to skim?

 

[CStrickland]

I like 10% per week too, it seems better than less frequent / more drastic changes. especially for the first year when nitrates might not be clearing as efficiently and you're figuring out how much to feed and your nutrient export regimen.

For sump flow I thought that 5X DT volume was standard. I think I got 3-5 from melev's sump info. I been daydreaming about my new skimmer all day (don't tell my professors ) so to use it as an example... an old school 150 nwb is decent for a 75, and if it's running the original OTP 5000 pump it's moving, at best, 125gph of water through the skimmer itself. Now, sure, the skimmer is not passing water straight through, so the dirty water is mixing in with the clean rather than just being processed, but still it seems like the point of diminishing return would be closer to 125 than to 600.

I bet there's a sweet spot where the amount of cleaning the skimmer peaks, and any faster and the water that's getting pumped out of the sump is only marginally cleaner than it went in (or marginally dirtier than it would be if it had a longer contact time with the skimmer). Sadly, I don't think anybody knows what that is. I did a fair amount of research when I built my sump a year ago and while people really yell and fuss a lot on both sides (fast and slow sumps) there's not much hard evidence. So no right answer. I bought a pump to move 5X dt volume incl rocks and sand after headloss. I was able to afford a nice sturdy little eheim because I didn't need that much push, quality over quantity I guess, lol

I bet if you run algae in your fuge, a little faster will keep cyano from growing. That's nice.

Lower sg is ok for fish, but coral do better a little higher. You can use sw to top off for evaporation to bring it up gently. I stay around 1.025 just cause that gives a little cushion where if it creeps up .001 it won't be a big deal. If your less scared and have a reliable ATO, 1.026 is good.

 

[Bent]

Thanks for the info .... I thought most of the current group I had liked sg between 1.020-1.025?.... I'll try to slowly raise it .... What should I raise it to 1.026?

I will eventually find the chocolate chip starfish a new home then

My emerald crab is very tiny so hopefully I will be good for a while

Also I read on here that around 5x turnover is good to give the skimmer in the sump enough time to skim?

If you raise it, make sure you do it slowly, like over the course of a couple of weeks. What you could do is let the evaporation raise it, keep measuring it every day until the SG gets to 1.026 and then add 1.026 new salt water to raise the water level to a normal operating level, then just keep it there. Your inhabitants will be fine at 1.023, its all about stability. But if you get any more critters that are a bit more picky about their salinity, you may run into issues. Again, its all about stability over chasing numbers. Someone who keeps a rock solid 1.023 will be more successful than someone else who keeps a wishy washy 1.026 and lets it go up and down with regular swings. Know what I mean?

But ideally, a solid 1.026 is your target number.

Sump throughput (I like calling it that) really depends on the skimmer. What brand and model skimmer is it? If its a good skimmer that is rate to 75g, you really need to put enough turnover through the sump to get new water to it for maximum effiencieny. If that makes any sense. Really I think the 10x volume number comes from the amount of gallons you want your skimmer filtering every hour.

 

[Sandnukka15]

Thanks guys the skimmer is an octopus hob that I rigged in the sump it's doing fairly well.... I can't rem the model but it's rated for 75 gallons I have another skimmer rather for 75 as well I might add

Sorry I forgot to mention that it's a fowlr tank so the salinity doesn't need to be on the high end


Thanks again for the help

 

[civics14]

Thanks guys the skimmer is an octopus hob that I rigged in the sump it's doing fairly well.... I can't rem the model but it's rated for 75 gallons I have another skimmer rather for 75 as well I might add

Sorry I forgot to mention that it's a fowlr tank so the salinity doesn't need to be on the high end


Thanks again for the help

Seems a bit odd you're having people recommend a 1.026 SG without asking what kind of tank you have. Most FOWLR tanks I seen run even lower than you - 1.021. However, like others said, stability is key, so if you have it at 1.023 - stay there.

I have a 65g w/ 20g sump as well. I have a skimmer and filter socks (change out every 3 days).

Live stock: 1 yellow tang, 2 clowns, 2 firefish, 1 damsel, neon dottyback, yellow coris wrasse, no idea the number of snails and hermits. It is a mixed tank with LPS, SPS, Zoas, & Anemones. Not sure how much rock I have. I feed three times a day in small portions, 1st - flakes, 2nd - mysis shrimp, 3rd - blended fresh seafood i made (oysters, octopus, smelt, shrimp, & seaweed).

I use to do bi-weekly water changes around 7-8g, now I do monthly 15-18g. This works for me for the past 10 months.

 

[g_langley]

There will be no detrimental effects with raising SG from 1.023 to say 1.025, that's what I run mine at, 1.025, and always have. But do it slowly, the evaporation technique is a good one.

 

[civics14]

There will be no detrimental effects with raising SG from 1.023 to say 1.025, that's what I run mine at, 1.025, and always have. But do it slowly, the evaporation technique is a good one.

There is no detrimental effect, but there is nothing to gain either for his set up. So why recommend it?

 

[CStrickland]

Unless someone says they're running fowlr I figure they plan to have some coral
Unless someone says they are exclusively coral, I assume they have some fish
Just cause most tanks on reefcentral have some reef going on

 

[Sandnukka15]

Yea im doing stictly fowlr .... im not ready to invest in intense lighting and corals as a newb in saltwater

 

[Bent]

There is no detrimental effect, but there is nothing to gain either for his set up. So why recommend it?

FOWLR or not, I always recommend what will be easiest and cause the least problems. While it's true most fish will do fine with a stable SG that's less than ideal, or even more than ideal, there are some that won't. So while some will thrive at different SGs, almost all will thrive at 1.026. So why start out at a handicap and set yourself up for possibly making a mistake that could have been completely avoided by keeping the SG at a more "blanket" level?

 

[Sandnukka15]

Does higher sg help deter ich and other problems?.... As in the higher end of what is comfortable for that spiecies of fish

The fish I have I have read 1.020-1.025 .... So will 1.026 be good for them

2 clowns
1 cardinal
1 fire fish
1 gramma basslet

 

[CStrickland]

I thought I read it was the opposite, that lower salinity is common for wholesalers cause fish stay healthier and it's cheaper cause they use less salt but higher is necessary for coral? Dunno, maybe a rumor. There's so much bad ich info out there that I only believe it if I've heard it from one of the three people on here that have stickied threads on the subject.

 

[Sandnukka15]

So now I'm confused should I slowly aim for 1.026 or clooser to 1.020