Will a 50% WC shock my fish?

So my nitrates have been hanging around 30 and istant ocean natural nitrate reducer hasn't been doing the trick. What I want to do is do a 50% water change 1 day, then another 50% 3 days after. My question is I have a 20 gallon tank that contains 1 clownfish, 1 cherub angelfish, and a small zoanthid colony. How can I do this without shocking and stressing my fish out?

 

You wont shock your fish but you might have a miny cycle and see some diatoms come up. You probably wont need it but just to be safe I would have some seachem prime on hand and test for ammonia just incase you have a small spike. In my experience large wc's like that didnt help with nitrates at all but you might. Give it a try and if it doesnt work try seachems purigen.

 

Generally a 50% water change isn't recommended unless it's a rather dire situation (ie: huge ammonia spike, a softie releasing toxins, etc). However, if you feel you must do this then ensure the following criteria: 1) pH of the new water matches the tank water, 2) the temperatures are the same, 3) the new water is thoroughly aerated, and 4) the new water's salinity matches the tank's.

This is a temporary solution however, because you need to figure out what is causing the high nitrates. I'm not familiar with IO natural nitrate reducer but it doesn't sound like it's a "natural" method of nitrate reduction.

Perhaps you could explain your current method of exporting/breaking down waste. Skimming? DSB? Refugium?

Other questions: how often are you doing water changes and are you overfeeding? Also, what is your water source?

These are things to consider regarding nitrates and perhaps someone else will chime in with additional ideas.

One more thought: if you do a 50% water change on day 1, your nitrates will (or should) go down to ~ 15. However, if you do a water change 3 days later, and assuming they don't escalate after the 1st water change, your nitrates will only be reduced to ~7-8 (which is pretty good).

 

I was using tap water with conditioner but now I am using rodi water. Im going to do a 50% water change once I get my salt ordered and in. Ill see where that takes me. If it works, Ill do another one. That should get me around 7-8 nitrates. After that I am just going to wait it out until they go to 0. Sound like a good idea?

 

oh and what exactly does seachem prime do? I use rodi water so I dont need another dechlorinator or should I still get it?

 

Seachem Prime locks up chlorine and chloramine as well as eliminates ammonia and nitrates. I believe it also has a slime coat beneficial for fish.

Where are you getting your RO/DI water from? It should be absent of nitrates unless the membrane is getting old thus it's not filtering the way it should be. You need a TDS meter to determine that; you could test the nitrates in the RO/DI water but it's my guess the nitrates are coming from overfeeding or poor nutrient export and/or breakdown.

 

I don't think 30 ppm of nitrates with only a zoa colony is that bad. I wouldn't do 50% maybe twenty % and find the cause ie over feeding. Thats just me

 

Why not do a 20% water change every other day a few times? Less shock on the fish...

 

Well I think the cause Is how when my tank cycled I had 30 nitrates and being a novice reefer, I added a fish. They have stuck around 30 ever since. Im gna do a 25% water every day for 3 days. I figured this should get me around 5 nitrates and then Ill start doing 10% every week how does this sound? Do you think it will affect my angel, clown, or zoas?

 

Doing big water changes will not cause a cycle .Bacteria live on surfaces not in the water column(for the most part). Diatoms feed on silicates which come from adding new sand not from adding fresh SW.However; changing parameters fast is not good for anything.People who try quick fixes invariably fail and leave the hobby broke and frustrated.There is no need to rush and our motto of "Go slow let it grow" is sound advice.While your nitrates are on the high side lowering them in a few days will put unneeded stress on the zoa's and fish.Zoa's actually prefer water on the dirtier side.My advice is to do 25 percent wc's once a week for a month and test your Nitrates either before or after each change.If they haven't decreased in that time you can increase the size of the weekly wc's until you figure out exactly how much water you need to change weekly to reach and hold the desired Nitrate level.You can help by cutting back on the frequency and ammount you are feeding.I would also suggest checking your test kit either with another kit or having your LFS check it for you to assure that your Nitrates are indeed high.