established tank high nitrates and ?'s

[tryin2make63]

okay , so very logical ? could my nitrates be high dues to this....
i have at least 5 gals of water evaporate a week from my lights and sump. when its time to do an pwc i do an 5 gal pwc and then add 5 gal freshwater to the tank to even out the sg.

 

[tryin2make63]

thats 10 gal. it comes out to a little less than 20% pwc

 

[Kurt_Nelson]

Don't fool yourself that you're doing a 20% water change. Several things are wrong with that. If your "My Tanks" is correct, you have a 20g sump in addition to the 58g tank. So 10g out of 78g is just shy of 13%.

In addition, that 5g that evaporated left behind all the nitrates, etc. I *wish* the nitrates evaporated away, but they don't. So you're only taking out 5g of water that has nitrates in it. That's just over 6% a week. That's not much.

While it doesn't help you with your nitrates, I'd suggest keeping on that evaporation a little more frequently that just once a week. Letting 5+% of your tank evaporate away before adding fresh water is going to be causing some really nasty salinity swings when you do that water change.

 

[tryin2make63]

i have noticed that the sp does get really high. where do you get 78? y not 68. then you have to take count for all the rock and sand right? 10 gal out of 68 is 15%... and thats per week

 

[mdaniel2882]

i have noticed that the sp does get really high. where do you get 78? y not 68. then you have to take count for all the rock and sand right? 10 gal out of 68 is 15%... and thats per week

the live rock probably does not take up 10 gal. it is very porus and holds a lot of water. you should top off your tank EVERY day. The water that you put into your tank to replace evaporated water does not count toward your water change. only the 5 gallons you repalced when you siphoned it out of your tank.

 

[cmor1701d]

Regardless of the actual water volume in the tank you need to a PWC of the tank volume (dry) and that does not include adding top off water. Evaporation as Kurt said needs to be replaced on a much more regular basis than 5 gallons/week. That's way too big a swing of SG. If you don't have a refractometer, get one and keep an eye on the SG. You will end up getting a ATO (Automatic Top Off) system before you know. I used to add a gallon+/day till I added my JBJ ATO. Now I refill my resovoir tank once a month.

If you do an actual 10 gallon PWC (remove 10 gallons and replace 10 gallons) per week that should suffice and help reduce/controil nitrates depending on where they are coming from.

 

[Kurt_Nelson]

i have noticed that the sp does get really high.

I'd do something about that, then.

where do you get 78? y not 68.

Well... 58 gallon tank plus 20 gallon sump = 78 gallons in my book. That's where I get it.

then you have to take count for all the rock and sand right? 10 gal out of 68 is 15%... and thats per week

Yeah... 10/68 is about 15% which is not "a little under 20%" as you said in your previous post. But as I said, 5 gallons of that is top off and doesn't dilute anything. So you're only changing 5 gallons.

I don't think when people give basic % figures for water change values, they're accounting for the volume taken up by sand and rock. That would kind of make the advice hard to give since everyone has different amounts of rock and sand in their tank.

Regardless of how you want to figure percentages, if I had your setup and was trying to lower nitrates, I'd be doing at LEAST a 15g water change each week - not including the water added for evaporation.

 

[tryin2make63]

if i hav an go gal long tank that i use as an sump you can not fill it all the way up sue to a power shortage it might overflow. therefore mine is only 1/2 full

 

[Kurt_Nelson]

Y'know... you can change the numbers and your reasoning all you want, but it doesn't change the fact that you're complaining about high nitrates and want help in reducing them. I'll just reiterate my final sentence of my last point and be done with this...

Regardless of how you want to figure percentages, if I had your setup and was trying to lower nitrates, I'd be doing at LEAST a 15g water change each week - not including the water added for evaporation.

Good luck.

 

[thincat]

+1

 

[tryin2make63]

i wasnt trying to argue. i was simply asking questions. guess i should have been more specific on my sump and how full it is. i do appreciate the comments and have started adding water daily. i do another water change tomorrow.

 

[tryin2make63]

changed 15 gallons last night. all water good except nitrates...20ppm

 

[browntrout]

My 75g tank never ever read below 20ppm nitrate. I did weekly water changes and used ro/di with a tds reading of 0. I tested everything. I finally stopped trying to reach zero. I kept SPS and CLAMS with zero issues. Now that I have a 135 tank with a sump/fuge and killer skimmer I can get down to zero, but 20 is fine.

 

[tryin2make63]

next water change is tomorrow. will give water per.

 

[Mitchell0605]

20ppm isn't bad. 10ppm is excellent. <5ppm is amazing.

 

[thincat]

Keep trying for 0 and whatever you come up with will be great. Please try to keep it 20 and below and you will be fine.

 

[tryin2make63]

okay here is the progress. did another 15 gal pwc. i also stopped by my lfs and baught some macro alage (looks really stringy) and put it in my refugium. still reading 20 ppm. everything else is great. i got coraline growing all over my glass. my zoas are amazing looking and i have this coral on a clam that came on my live rock that i dont know what is but it seems to be doing fine. just this 20 is bothering me

 

[thincat]

Nothing happens fast in a saltwater tank. So give your macro algae a chance. It sounds like you got come Chaeto algae which is good. Don't pack it in to tight because that will cause the inner side to die off. It like to tumble if you can. I can't so I turn them ever so often.

 

[bavass]

My nitrates were 160ppm and I started doing 2 25g water changes on a 55g tank. Did one on Sunday and one on Wed. The nitrates dropped pretty quick till I hit 20ppm after that it was a slow process. My nitrates are down to 2-5ppm. So stay on it and dont give up. Just keep fighting